Category Archives: Cranial Base

Update Cerebellopontine angle epidermoid cyst

The cerebellopontine angle epidermoid cyst is a posterior fossa epidermoid cyst.

It account for 3-6% of cerebellopontine angle tumors. Comparatively, vestibular schwannomas, the most common CPA angle tumor, account for 85%.

Men and women are equally affected and the symptoms usually arise between the mid-20’s and early 50’s 1) with a mean age of 38.8 years at presentation 2).

Pathophysiology

Although several mechanisms for cranial nerve dysfunction due to these tumors have been proposed.

Hasegawa et al. report the first direct evidence of etiology of cranial nerve dysfunction caused by cerebellopontine angle epidermoid tumors. Young age and rapidly progressive neurological deficit might be the characteristics for strangulation of the affected nerves by the cyst capsule 3).

Clinical features

CPA epidermoid cysts can compress the surrounding cranial nerves, brainstem, and cerebellum. Ataxia and cranial nerve palsies often result 4).Thirty cases of cerebellopontine angle epidermoid cysts treated over a period of 20 years werw reviewed with regard to their clinical features, the pathophysiology of their symptoms and their management. The predominating symptoms were related to the 7th and 8th cranial nerves and headaches. The signs and symptoms were present for an average period of 4 months. It was not always possible to determine if the signs and symptoms were due to local involvement by the epidermoid, increased intracranial pressure, or both 5).

Diagnosis

Diagnostic procedures evolved from angiography and ventriculography to non-invasive computed tomography and MRI 6).


cerebelloponineangleepidermoidcyst.jpg

Treatment

The posterior cranial fossa approach was used in 27 cases in the case series of deSouza et al. Total excision of the epidermoid was the aim and was carried out in five (18%) patients but concern regarding the preservation of nearby important neurovascular structures forced partial removal in 22 patients. To minimise reformation, the residual epidermoid was carefully coagulated with the aid of the operating microscope and bipolar cautery without damaging surrounding neurovascular structures 7).


The characteristics of epidermoid cysts make them amenable to whole course neuroendoscopic resection. Use of physiologic/pathologic interspaces and neuroendoscopic angulations decreases traction on the brain, improves complete resection rates, and decreases postoperative complications 8).

Case series

2016

Twenty-two cases with epidermoid cysts of CPA micro-neurosurgically treated since 2005 were reviewed. Clinical status of the patients before the surgery and post-operative functional outcome were recorded. Available data from the English literature were summarized for comparison. Mass reduction of cyst contents in most cases was usually associated with prompt and marked improvement of the symptoms suggesting neuroapraxia caused by compression of the tumor content and/or mild ischemia. Among them, two cases showed strangulation of the affected nerves by the tumor capsule whose preoperative dysfunction did not improve after surgery in spite of meticulous microsurgical removal of the lesion. Involved facial and abducent nerves in these two cases showed distortion of nerve axis and nerve atrophy distal to the strangulation site.

Hasegawa et al. report the first direct evidence of etiology of cranial nerve dysfunction caused by cerebellopontine angle epidermoid tumors. Young age and rapidly progressive neurological deficit might be the characteristics for strangulation of the affected nerves by the cyst capsule. Even though the number of cases might be limited, immediate decompression and release of the strangulating band might be urged in such patients to prevent irreversible deficits 9).


17 patients, including 7 with tumor limited to the cerebellopontine angle, 7 with cerebellopontine angle tumor penetrating supratentorially, and 3 with cerebellopontine angle tumor extending along skull base to contralateral cerebellopontine angle. All patients were followed-up for the mean duration of 126 months.

On admission cranial nerve symptoms predominated. Total tumor removal was achieved in 5 patients, and incomplete removal (with small tumor remnants left on vessels, nerves, or brainstem) in 12 patients. Postoperatively, preoperative deficits worsened in 2 and new postoperative deficits occurred in 10 patients. The extent of tumor expansion had no effect on postoperative morbidity and risk of recurrence. During long-term follow-up, improvement or resolution of preoperative deficits was seen in 11 of 17 patients, and new postoperative deficits in 8 of 10 patients. Symptomatic recurrences after an average of more than 9 years were noted in 5 patients, 3 of whom were reoperated. Recurrences occurred in some younger patients and always in area of primary tumor. No effect of extent of tumor removal on risk of recurrence was found.

The extent of tumor removal had no effect on the risk of recurrence, and thus it may be acceptable to leave tumor capsule fragments adhering closely to nerves, vessels, or brainstem. During long-term follow-up, resolution or improvement of present preoperatively and new postoperative neurological deficits may be expected in most patients 10).

2015

In a case series, pathophysiology of cranial nerve dysfunction in CPA epidermoid cysts was evaluated with special attention to a new mechanism of capsule strangulation caused by stratified tumor capsule. Twenty-two cases since 2005 were reviewed. Clinical status of the patients before the surgery and post-operative functional outcome were recorded. Available data from the English literature were summarized for comparison. Mass reduction of cyst contents in most cases was usually associated with prompt and marked improvement of the symptoms suggesting neurapraxia caused by compression of the tumor content and/or mild ischemia. Among them, two cases showed strangulation of the affected nerves by the tumor capsule whose preoperative dysfunction did not improve after surgery in spite of meticulous microsurgical removal of the lesion. Involved facial and abducent nerves in these two cases showed distortion of nerve axis and nerve atrophy distal to the strangulation site. Hasegawa et al. report the first direct evidence of etiology of cranial nerve dysfunction caused by cerebellopontine angle epidermoid tumors. Young age and rapidly progressive neurological deficit might be the characteristics for strangulation of the affected nerves by the cyst capsule. Even though the number of cases might be limited, immediate decompression and release of the strangulating band might be urged in such patients to prevent irreversible deficits 11)


Hu et al. performed a retrospective analysis of clinical data of 13 male and 17 female patients (mean age: 42.4 ± 11.4 years) who presented with a CPA epidermoid cyst and underwent whole course neuroendoscopy. Complications and tumor recurrence were assessed at follow-up. Results Clinical manifestations included an initial symptom of headache (n = 21), gait instability (n = 6), intracranial hypertension (n = 13), posterior cranial nerve symptoms (n = 6), ataxia (n = 5), and hydrocephalus (n = 1). All patients tolerated tumor resection with subsequent symptomatic improvement, and the results of the postoperative magnetic resonance imaging scan did not show any remnants of tumor. Mean duration of surgery was 2.61 ± 0.47 hours, mean loss of blood was 96.8 ± 35.4 mL, and the mean duration of hospitalization was 7.5 ± 2.25 days. Postoperative complications (8 of 30 [26.7%]) included fever (n = 5), communicating hydrocephalus (n = 1), facial nerve paralysis (n = 1), and abducens nerve palsy (n = 1). Tumor recurrence was observed in two patients (6.7%). No deaths or intracranial hemorrhage was reported.

The characteristics of epidermoid cysts make them amenable to whole course neuroendoscopic resection. Use of physiologic/pathologic interspaces and neuroendoscopic angulations decreases traction on the brain, improves complete resection rates, and decreases postoperative complications 12).

2010

Between 1996 and 2004, 10 patients with typical symptoms of trigeminal neuralgia were found to have cerebellopontine angle epidermoids and treated surgically.

Total resection was done in 6 patients (60%). Surgical removal of tumor and microvascular decompression of the trigeminal nerve were performed simultaneously in one case. One patient died due to postoperative aseptic meningitis. The others showed total relief from pain. During follow-up, no patients experienced recurrence of their trigeminal neuralgia (TN).

The clinical features of TN from CPA epidermoids are characterized by symptom onset at a younger age compared to TN from vascular causes. In addition to removal of the tumor, the possibility of vascular compression at the root entry zone of the trigeminal nerve should be kept in mind. If it exists, a microvascular decompression (MVD) should be performed. Recurrence of tumor is rare in both total and subtotal removal cases, but long-term follow-up is required 13).

1989

Thirty cases of cerebellopontine angle epidermoid cysts treated over a period of 20 years are reviewed with regard to their clinical features, the pathophysiology of their symptoms and their management. The predominating symptoms were related to the 7th and 8th cranial nerves and headaches. The signs and symptoms were present for an average period of 4 months. It was not always possible to determine if the signs and symptoms were due to local involvement by the epidermoid, increased intracranial pressure, or both. Diagnostic procedures evolved from angiography and ventriculography to non-invasive computed tomography and MRI. The posterior cranial fossa approach was used in 27 cases. Total excision of the epidermoid was the aim and was carried out in five (18%) patients but concern regarding the preservation of nearby important neurovascular structures forced partial removal in 22 patients. To minimise reformation, the residual epidermoid was carefully coagulated with the aid of the operating microscope and bipolar cautery without damaging surrounding neurovascular structures 14).

Case reports

2016

Malignant transformation of a residual cerebellopontine angle epidermoid cyst 15).

2015

Guan et al. the case of a 13-year-old female with a newly diagnosed cerebellopontine angle EC who presented with worsening headaches, photophobia, and emesis. Magnetic resonance imaging demonstrated significant pericystic brainstem edema and mass effect with effacement of the fourth ventricle. Refractory symptoms prompted repeat imaging, revealing cyst enlargement and dense rim enhancement. Resection of the EC resolved both her symptoms and the brainstem edema. This case documents the radiographic evolution of EC rupture and subsequent clinical course 16).


A case of an unusual epidermoid cyst of the cerebellopontine angle extending into the upper cervical canal that appeared hyper-dense on computed tomography scanning, hyper-intense on T1-weighted magnetic resonance (MR) images, and hypo-intense on T2-weighted MR images 17).

1)

Fleming JF, Botterell EH. Cranial dermoid and epidermoid tumors. Surg Gynecol Obstet. 1959;109:403–411.
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Fawcitt RA, Isherwood I. Radiodiagnosis of intracranial pearly tumours with particular reference to the value of computer tomography. Neuroradiology. 1976;11:235–242.
3) , 11)

Hasegawa M, Nouri M, Nagahisa S, Yoshida K, Adachi K, Inamasu J, Hirose Y, Fujisawa H. Cerebellopontine angle epidermoid cysts: clinical presentations and surgical outcome. Neurosurg Rev. 2015 Nov 14. [Epub ahead of print] PubMed PMID: 26566990.
4)

Berger M, Wilson C. Epidermoid cysts of the posterior fossa. J Neurosurg. 1985;62:214–219.
5) , 6) , 7) , 14)

deSouza CE, deSouza R, da Costa S, Sperling N, Yoon TH, Abdelhamid MM, Sharma RR, Goel A. Cerebellopontine angle epidermoid cysts: a report on 30 cases. J Neurol Neurosurg Psychiatry. 1989 Aug;52(8):986-90. PubMed PMID: 2795068; PubMed Central PMCID: PMC1031839.
8) , 12)

Hu Z, Guan F, Kang T, Huang H, Dai B, Zhu G, Mao B, Kang Z. Whole Course Neuroendoscopic Resection of Cerebellopontine Angle Epidermoid Cysts. J Neurol Surg A Cent Eur Neurosurg. 2015 Aug 24. [Epub ahead of print] PubMed PMID: 26302403.
9)

Hasegawa M, Nouri M, Nagahisa S, Yoshida K, Adachi K, Inamasu J, Hirose Y, Fujisawa H. Cerebellopontine angle epidermoid cysts: clinical presentations and surgical outcome. Neurosurg Rev. 2016 Apr;39(2):259-66; discussion 266-7. doi: 10.1007/s10143-015-0684-5. PubMed PMID: 26566990.
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Czernicki T, Kunert P, Nowak A, Wojciechowski J, Marchel A. Epidermoid cysts of the cerebellopontine angle: Clinical features and treatment outcomes. Neurol Neurochir Pol. 2016;50(2):75-82. doi: 10.1016/j.pjnns.2015.11.008. PubMed PMID: 26969562.
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Son DW, Choi CH, Cha SH. Epidermoid tumors in the cerebellopontine angle presenting with trigeminal neuralgia. J Korean Neurosurg Soc. 2010 Apr;47(4):271-7. doi: 10.3340/jkns.2010.47.4.271. PubMed PMID: 20461167; PubMed Central PMCID: PMC2864819.
15)

Pikis S, Margolin E. Malignant transformation of a residual cerebellopontine angle epidermoid cyst. J Clin Neurosci. 2016 Nov;33:59-62. doi: 10.1016/j.jocn.2016.04.008. Review. PubMed PMID: 27519146.
16)

Guan Z, Hollon T, Bentley JN, Garton HJ. Ruptured pediatric cerebellopontine angle epidermoid cyst: a case report detailing radiographic evolution and clinical course. J Neurosurg Pediatr. 2015 Aug 21:1-5. [Epub ahead of print] PubMed PMID: 26295366.
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Lim J, Cho K. Epidermoid cyst with unusual magnetic resonance characteristics and spinal extension. World J Surg Oncol. 2015 Aug 7;13:240. doi: 10.1186/s12957-015-0651-1. PubMed PMID: 26245481; PubMed Central PMCID: PMC4527251.

Update: Intracanalicular vestibular schwannoma

The current practitioner is more often managing intracanalicular vestibular schwannomas than in the past, as improved imaging and heightened awareness leads to earlier diagnosis of these tumors.

Case courtesy of Dr Ian Bickle, <a href=“https://radiopaedia.org/”>Radiopaedia.org</a>. From the case <a href=“https://radiopaedia.org/cases/48853”>rID: 48853</a>

Differential diagnosis

Intracanalicular meningioma


Pantopaque (iophendylate) is an oily contrast medium historically used during spine imaging. Due to its persistence in the subarachnoid space and the potential to lead to severe arachnoiditis, it is no longer used today. Deep et al., present a 40-year-old male with new-onset headaches, imbalance, and vertigo. Brain magnetic resonance imaging revealed a 2-mm T1 -hyperintense intracanalicular lesion. Numerous hyperdense foci were scattered throughout the subarachnoid space on computed tomography. Further history revealed the patient received Pantopaque 30 years prior, after sustaining spinal trauma. Remnant Pantopaque contrast is an important differential when evaluating a patient with a suspected intracranial tumor in order to avoid unwarranted surgical intervention 1).


A 46-year-old man with venous compression of the vestibulocochlear nerve inside the internal auditory canal (IAC). The patient presented with a 2-year history of recurrent attacks of disabling vertigo and intermittent high-frequency tinnitus on the right side. Magnetic resonance images showed a small, contrast-enhancing lesion in the fundus of the right IAC, which was suspicious for vestibular schwannoma. During surgical exploration, a large venous loop was found extending into the IAC and compressing the vestibulocochlear nerve. The vessel was mobilized and rerouted out of the IAC. The presumed vestibular schwannoma at the cochlear fossa was left in situ. The patient’s symptoms resolved immediately after surgery. Hearing was unchanged postoperatively. On follow-up, there has been no growth of the contrast-enhancing lesion in the IAC for 3 years so far.Disabling vertigo can also be caused by venous microvascular compression of the vestibulocochlear nerve inside the IAC and may be treated successfully by microvascular decompression. A sensitive, conservative approach to lesions in the fundus may be justified in the presence of an additional, more prominent pathology that causes compression of the vestibulocochlear nerve 2).

Treatment

The role of observation, microsurgery, and radiation treatment in the management of intracanalicular tumors continues to evolve.

Watchful waiting is an important management option for patients with minimal symptoms. The literature on the natural history of small vestibular schwannomas continues to expand, with particular emphasis on the expected hearing outcomes.

Microsurgical techniques also focus on hearing preservation. Presence of fundal fluid and good or normal hearing preoperatively are positive predictors of hearing preservation after surgery. Long-term follow-up after radiation therapy for vestibular schwannomas continues to demonstrate excellent tumor control rates, although hearing preservation rates are modest.

Multiple factors, including status of hearing, presence of vestibular symptoms, patient age, medical comorbidities, institutional outcomes, and patient preferences, help determine the management strategy for patients with an intracanalicular vestibular schwannoma 3).


Complete surgical removal of intracanalicular vestibular schwannomas with nerve VII and VIII sparing and without worsening patient’s status is challenging. Also the choice of an optimal surgical technique, which is usually limited to selection between retrosigmoid transmeatal (RT) and middle fossa (MF) approach, can be a challenge. Although many previous studies documented superiority of RT to MF approach and vice versa, still no consensus has been reached regarding an optimal approach to intracanalicular vestibular schwannomas. In a technical note, Turek et al., present RT approach with an endoscopic assistance and highlight its advantages over MF approach in surgical management of pure intracanalicular vestibular schwannomas.

RT approach with an endoscopic assistance is presented as an optimal surgical treatment for intracanalicular vestibular schwannomas, and its advantages are compared to those offered by MF approach.

Under an endoscopic guidance, they found a residual tumor in the fundus of the inner acoustic canal and performed its gross total resection.

RT approach is an excellent technique suitable for safe radical surgical treatment of T1 vestibular schwannomas; this technique is associated with lower morbidity risk than MF approach 4).


A longitudinal study of a series of consecutive patients operated on with the 2 techniques by the same surgeon was conducted. Selection criteria included tumor confined to the internal auditory canal (IAC) with a length ranging from 4 to 12 mm and hearing class A or B. Patients were alternately assigned to 1 of the 2 groups regardless of auditory class and distance of the tumor from the IAC fundus. Thirty-five subjects were operated on with the RS-TM technique and 35 via the MF route.

No significant differences in auditory and facial nerve function results between the 2 techniques were observed. The RS-TM approach, however, showed better facial nerve results at discharge. VS size, IAC enlargement, and, particularly, the distance from the IAC fundus were found to influence the postoperative results more than the type of approach itself.

The MF approach has been described as being the better technique for VS surgery in terms of auditory results. However, this claim lacks statistical substantiation because no prospective studies are to be found in the literature. The present longitudinal investigation shows that the MF approach does not afford any particular advantages over the RS-TM route in terms of auditory results in intracanalicular VS, with the exception of tumors reaching the IAC fundus 5).

Case series

2016

A retrospective study was done in 14 patients who underwent MFA for vestibular schwannoma in Asan Medical Center.

The median age at diagnosis was 46.3 years. At initial presentation, 57% of the patients had vertigo, 43% hearing disturbance, and 64% tinnitus. The mean tumor size was 9.7 mm. The tumors were completely resected in 86% of the patients. Hearing was post-operatively preserved in 12 patients and two patients lost their hearing following surgery. Facial nerve function post-operatively remained unchanged in 12 patients (86%) 6).


A retrospective analysis of 19 patients with intracanalicular VS and disabling vestibular dysfunction as the main or only symptom (Group A). All of the patients reported having had disabling vertigo attacks. Subjective evaluation of the impairment of patients was performed before surgery, 3 weeks after surgery, 3 months after surgery, and 1 year after surgery, using the Dizziness Handicap Inventory (DHI). The main outcome measures were improvement in quality of life as measured using the DHI, and general and functional outcomes, in particular facial function and hearing. Patient age, preoperative tumor size, preoperative DHI score, and preservation of the nontumorous vestibular nerve were tested using a multivariate regression analysis to determine factors affecting the postoperative DHI score. The Mann-Whitney U-test was used to compare the postoperative DHI score at 3 weeks, 3 months, and 1 year after surgery with a control group of 19 randomly selected patients with intracanalicular VSs, who presented without vestibular symptoms (Group B). The occurrence of early postoperative discrete vertigo attacks was also compared between groups. RESULTS The preoperative DHI score was ≥ 54 in all patients. All patients reported having had disabling rotational vertigo before surgery. The only significant factor to affect the DHI outcome 3 weeks and 3 months after surgery was the preoperative DHI score. The DHI outcome after 1 year was not affected by the preoperative DHI score. Compared with the control group, the DHI score at 3 weeks and 3 months after surgery was significantly worse. There was no significant difference between the groups after 1 year. Vertigo was improved in all patients and completely resolved after 1 year in 17 patients.

Disabling vestibular dysfunction that affects quality of life should be considered an indication for surgery, even in otherwise asymptomatic patients with intracanalicular VS. Surgical removal of the tumor is safe and very effective in regard to symptom relief. All patients had excellent facial nerve function within 1 year after surgery, with a very good chance of hearing preservation 7).


156 patients diagnosed with an intracanalicular VS managed conservatively.

After a follow-up of 9.5 years, tumor growth had occurred in 37% and growth into the cerebellopontine angle had occurred in 23% of patients. Conservative treatment failed in 15%. The pure tone average had increased from 51- to 72-dB hearing level, and the speech discrimination score (SDS) had decreased from 60% to 34%. The number of patients with good hearing (SDS > 70%) was reduced from 52% to 22%, and the number of patients with American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A hearing was reduced from 19% to 3%. Hearing was preserved better in patients with 100% SDS at diagnosis than in patients with even a small loss of SDS. Serviceable hearing was preserved in 34% according to AAO-HNS (class A-B) and in 58% according to the word recognition score (class I-II). Rate of hearing loss was higher in patients with growing tumors.

Tumor growth occurred in only a minority of patients diagnosed with an intracanalicular VS during 10 years of observation. The risk of hearing loss is small in patients with normal discrimination at diagnosis. Serviceable hearing is preserved spontaneously in 34% according to AAO-HNS and in 58% according to the word recognition score 8).

2014

31 patients who were followed up for more than 1 year among patients diagnosed as having VS limited to the internal auditory canal. The median follow-up period was 31 months (range, 12-84 mo). We analyzed the patients’ clinical features, clinical courses, and audiologic changes.

The most frequent initial presenting symptom in patients with ICVS was hearing loss, and one-half of the patients (8 of 16) had a history of sudden hearing loss. Seven patients (22.5%) showed tumor growth during the follow-up period. When we considered the initial tumor size in ICVS, the patients larger in size than the median showed a significantly higher rate of tumor growth. In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were classified as Class A (normal hearing) and six patients were classified as Class B. Only one patient among patients with useful hearing (Classes A and B) showed tumor growth. The follow-up hearing levels of all Class A patients were preserved; however, all Class B patients deteriorated to Class C.

Patients with ICVS showed favorable results with conservative management. Among them, patients with small tumors and normal hearing showed a good prognosis 9).

2011

47 patients with a unilateral intracanalicular vestibular schwannoma. Evaluation of growth was monitored by repeat MRI scanning. Repeated pure-tone and speech audiometry results were evaluated for subgroups of patients showing growth or no growth and by subsite location of tumor in the internal auditory canal.

Patients had a mean follow-up of 3.6 years. Over the entire population, the pure-tone average thresholds at 0.5, 1, 2, and 3 kHz and the word recognition scores both significantly deteriorated from 38 to 51 dB HL, and from 66% to 55%, respectively. Overall, 74% of subjects with good hearing, according to the 50/50 rule, maintained hearing above this rule. There were no significant differences in hearing loss by subsite in the internal auditory canal (porus, fundus, central) or by growth status (stable, growing, shrinking). Only 6 patients showed a large hearing change. This happened early during follow-up, with relatively stable hearing after this.

Hearing will deteriorate in some intracanalicular vestibular schwannomas, regardless of tumor growth. Hearing deterioration, if on a large scale, most likely occurs early in follow-up. The present results using conservative management in these tumors appear similar to those reported for stereotactic radiotherapy or microsurgery 10).

2008

Forty-seven patients (22 men and 25 women) harboring an intracanalicular vestibular schwannoma were followed prospectively. Mean age at the time of inclusion was 54.4 (20-71) years. The mean follow-up period was 43.8 months (+/-40 months) ranging from 9 to 222 months. Failure was defined as significant tumor growth and/or hearing deterioration that required a microsurgical or radiosurgical treatment. Failure was observed in 35 cases while a conservative treatment is still ongoing in 12 patients. Ten patients kept an unchanged tumor size (21.3%), while 36 patients experienced a tumor growth (76.6%), and 1 patient experienced a mild decreased tumor size (2.1%). Among the 40 patients who where available for hearing level study, 24 patients (60%) did not change their Gardner and Robertson hearing class. Fifteen patients (37.5%) experienced a >10-dB hearing loss and 2 of them became deaf. One patient (2.5%) improved her hearing level from 56.3 to 43.8 dB over a 39.5-month follow-up period. These data suggest that the wait and see policy exposes the patient to degradation of hearing and tumor growth. Both events may occur in an independent way in the middle-term period. This information has to be given to the patient, and a careful sequential follow-up may be adopted when the wait and see strategy is chosen 11).


Between 1987 and 2003, 96 patients (65 men and 31 women) underwent gamma knife stereotactic radiosurgery (SRS) for intracanalicular tumors. The median patient age was 54 years (range, 22-80 years). Hearing was graded using the Gardner-Robertson (GR) and the American Academy of Otolaryngology-Head and Neck Surgery classifications. Dose planning was performed on intraoperative stereotactic images using multiple 4-mm isocenters. The median tumor volume was 0.112 mm3 (range, 0.05-0.447 mm3), and the median margin dose was 13 Gy (range, 10-18 Gy).

The mean and median audiologic follow-up periods were 42 months and 28 months (range, 12-144 months), respectively. Serviceable hearing was preserved in 31 of 40 (77.5%) patients with initial American Academy of Otolaryngology-Head and Neck Surgery Class A hearing. Serviceable hearing was preserved in 40 of 79 (64.5%) patients with GR Grade I or II pre-SRS hearing. Ninety-two patients had GR Grade I, II, or III hearing before SRS, and GR Grade I, II, or III hearing was maintained in 78 patients (85%). Hearing grades improved in 7 patients. Facial and trigeminal nerve function was preserved in all patients. The tumor control rate (freedom from additional intervention) was 99.0% (95 of 96) at a median follow-up of 28 months (range, 12-144 months). One patient underwent tumor resection 18 months after radiosurgery.

SRS is a minimally invasive first-line management option for patients with intracanalicular tumors and provides high rates of hearing preservation with minimal morbidity 12).

2000

40 patients with 40 unilateral VS in the period 1973 to 1996 (mean 3.6 years). Twenty-seven tumours (67.5%) revealed growth and 13 tumours (32%) had no measurable growth. Four growth patterns were observed: (i) 15 tumours (37.5%) exhibited constant growth; (ii) 13 tumours (32.5%) had no measurable growth; (iii) 8 tumours (20%) revealed growth subsequent to a no-growth period; and (iv) 4 tumours (10%) manifested different growth patterns during the observation period. The mean diameter growth per year was 3.2 mm. The findings of the present study, especially those achieved in groups B (the non-growing tumours) and C (tumour growth subsequent to a silent period), question the reliability of the results achieved by radiosurgery, as no tumour growth may occur with no intervention13).

Case reports

2008

A unique case of unilateral widening of the internal auditory canal (IAC) with no significant contact with an ipsilateral intracanalicular vestibular schwannoma (VS), raising the issue of the cause(s) of this IAC widening.

The medical record and radiologic data were reviewed of a patient presenting an enlarged unilateral IAC, which led to the diagnosis of an intracanalicular VS that could not account for the dilation.

The patient had a unilateral dilation of the IAC that did not match the ipsilateral VS he had. As a result, this case motivated discussion of whether such dilation of the IAC was congenitally asymmetrical or the result of the mechanisms involved in the widening of the IAC.

Although asymmetry of IAC is a current notion, this case demonstrates a contrario that increased pressure exerted on the walls of the IAC cannot be the only mechanism in such widening 14).

2004

The first reported case of hemifacial spasm responsive to gamma knife radiosurgery in a patient with an intracanalicular vestibular schwannoma. Both the resolution of the spasm as well as tumor growth control were achieved with a single session of gamma knife radiosurgery. We report a 49-year-old male patient with a 6-month history of right-sided hearing loss and hemifacial spasm. MR examination revealed an intracanalicular vestibular schwannoma. The patient was treated with radiosurgery and received 13 Gy to the 50 % isodose line. Tumor growth control was achieved and no change in the tumor volume was present at the last follow-up at 22 months. The hemifacial spasm completely resolved after one year. Surgical removal of the presumably causative mass lesion has been reported to be the sole treatment in secondary hemifacial spasm. This case report indicates that it may be responsive to gamma knife radiosurgery. Whether or not this might be a treatment option in selected refractory cases of hemifacial spasm remains to be defined 15).

2002

A 68-year-old man with complete deafness of the left ear since childhood, who developed sudden, profound sensorineural hearing loss in the right ear. Magnetic resonance imaging revealed a small right-sided intracanalicular tumor. Treatment with high-dose corticosteroids produced only minimal improvement in hearing. Subsequent emergency decompression and resection of a VS resulted in rapid improvement and restoration of hearing, with facial nerve preservation. Although most neurotologic lesions in patients with hearing in only one ear are managed nonsurgically, resection of small tumors in the setting of sudden hearing loss should be considered in selected cases. This finding indicates that a therapeutic window may exist during which sudden hearing loss caused by intracanalicular tumors is reversible 16).

1998

An unusual case in which they recognized an additional branch arising from the jugular bulb. Three-dimensional computed tomography (3-D CT) revealed this anomaly beforehand, enabling us to avert excessive bleeding upon resection of the tumour. The abnormal vein was thought to be a remnant of the petrosquamosal sinus in the embryonic stage 17).


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10) Pennings RJ, Morris DP, Clarke L, Allen S, Walling S, Bance ML. Natural history of hearing deterioration in intracanalicular vestibular schwannoma. Neurosurgery. 2011 Jan;68(1):68-77. doi: 10.1227/NEU.0b013e3181fc60cb. PubMed PMID: 21099722.
11) Roche PH, Soumare O, Thomassin JM, Régis J. The wait and see strategy for intracanalicular vestibular schwannomas. Prog Neurol Surg. 2008;21:83-8. doi: 10.1159/000156710. PubMed PMID: 18810203.
12) Niranjan A, Mathieu D, Flickinger JC, Kondziolka D, Lunsford LD. Hearing preservation after intracanalicular vestibular schwannoma radiosurgery. Neurosurgery. 2008 Dec;63(6):1054-62; discussion 1062-3. doi: 10.1227/01.NEU.0000335783.70079.85. PubMed PMID: 19057318.
13) Thomsen J, Charabi S, Tos M, Mantoni M, Charabi B. Intracanalicular vestibular schwannoma–therapeutic options. Acta Otolaryngol Suppl. 2000;543:38-40. PubMed PMID: 10908971.
14) Kania RE, Herman P, Guichard JP, Tran Ba Huy P. [Dilation of the internal auditory canal and intracanalicular vestibular schwannoma: what are the mechanisms involved?]. Ann Otolaryngol Chir Cervicofac. 2008 Nov;125(5):256-60. doi: 10.1016/j.aorl.2008.07.006. French. PubMed PMID: 18786666.
15) Peker S, Ozduman K, Kiliç T, Pamir MN. Relief of hemifacial spasm after radiosurgery for intracanalicular vestibular schwannoma. Minim Invasive Neurosurg. 2004 Aug;47(4):235-7. PubMed PMID: 15346321.
16) Meiteles LZ, Liu JK, Couldwell WT. Hearing restoration after resection of an intracanalicular vestibular schwannoma: a role for emergency surgery? Case report and review of the literature. J Neurosurg. 2002 Apr;96(4):796-800. PubMed PMID: 11990824.
17) Tsutsumi T, Tsunoda A, Shimamoto K, Komatsuzaki A. Aberrant jugular bulb vein obstructing approach to intracanalicular vestibular schwannoma. J Laryngol Otol. 1998 Aug;112(8):772-4. PubMed PMID: 9850321.

Update: Cerebellopontine angle lipoma

Characteristically lipomas of the CPA have the facial nerve and vestibulocochlear nerve coursing through it on their way to the IAM. They are associated with intravestibular lipomas and sensorineural hearing loss.

Epidemiology

They account for ~10% of all intracranial lipomas.

Diagnosis

Radiographic features

MRI brain Signal characteristics are those of a lipoma

T1: high signal

images.radiopaedia.org_images_2107232_e3e8537790364cc8a2404efc00cdd4_gallery.jpg

https://images.radiopaedia.org/images/2107232/e3e8537790364cc8a2404efc00cdd4_gallery.jpg

T2: high signal

true FISP/FIESTA: low signal margin due to chemical shift artefact fat saturated sequences: shows signal dropout.

http://www.otosurgery.org/DJL_NEWSITE%20images/MRI_cpa-lipoma.gif

Differential diagnosis

Cerebellopontine angle tumors (CPA) are frequent; vestibular schwannomas and cerebellopontine angle meningiomas represent the great majority of such tumors. However, a large variety of unusual lesions can also be encountered in the CPA. The site of origin is the main factor in making a preoperative diagnosis for an unusual lesion of the CPA. In addition, it is essential to analyze attenuation at computed tomography (CT), signal intensity at magnetic resonance (MR) imaging, enhancement, shape and margins, extent, mass effect, and adjacent bone reaction. CPA masses can primarily arise from the cerebellopontine cistern and other CPA structures (arachnoid cyst, nonacoustic schwannoma, aneurysm, melanoma, miscellaneous meningeal lesions) or from embryologic remnants (epidermoid cyst, dermoid cyst, lipoma). Tumors can also invade the CPA by extension from the petrous bone or skull base (cholesterol granuloma, paraganglioma, chondromatous tumors, chordoma, endolymphatic sac tumor, pituitary adenoma, apex petrositis). Finally, CPA lesions can be secondary to an exophytic brainstem or ventricular tumor (glioma, choroid plexus papilloma, lymphoma, hemangioblastoma, ependymoma, medulloblastoma, dysembryoplastic neuroepithelial tumor). A close association between CT and MR imaging findings is very helpful in establishing the preoperative diagnosis for unusual lesions of the CPA 1).


The differential for lesions with high T1 signal includes:

haemorrhagic vestibular schwannoma

neurenteric cyst

thrombosed berry aneurysm

white epidermoid

ruptured intracranial dermoid

Treatment

They are not associated with malformations and can become symptomatic in a slowly progressive way by affecting the more susceptible of the cranial nerves in this region. As a result of the rare occurrence, the experience in treating and managing these tumors is limited. Consequently, the recommendations for treatment and for the role of surgery are very variable 2).

Free article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1656654/pdf/skullbasesurg00018-0039.pdf

Resections are considered in symptomatic patients who are refractory to targeted medical therapies, but at those stages the lipomas have often reached considerable sizes and encompass critical neurovascular structures.

Scoring system

The objective of a study is to develop and to evaluate the utility of a scoring system for CPA lipomas. The hypothesis is that CPA lipomas with lower scores are probably best managed with early surgery.

The PubMed database was searched using relevant terms. Data on patient and lipoma characteristics were extracted and used to design a scoring system. CPA lipomas were stratified by scores with corresponding managements and outcomes analyzed.

One hundred and seventeen patients with CPA lipomas were identified and 40 CPA lipomas were scored. The remaining CPA lipomas were deficient in data and not scored. No lipomas were scored as 1. Score 2 lipomas (n = 12; 30%) most often underwent serial surveillances (n = 5; 41.6%), with the majority of symptoms remaining unimproved (n = 2; 40%). Patients with score 2 CPA lipomas treated with medical therapies (n = 3; 25%) often experienced symptom resolution (n = 2; 66.6%) (p = 0.0499). Patients with score 2 CPA lipomas undergoing surgical resections (n = 3; 25%) all experienced symptom resolution (n = 3; 100%) (p = 0.0499). Score 3 was most common (n = 16; 40%) and these lipomas were often surgically resected (n = 10; 62.5%). The majority of patients with score 3 CPA lipomas having undergone surgical resections (n = 10; 62.5%) experienced symptom improvement (n = 1; 10%) or resolution (n = 4; 40%).

Score 2 CPA lipomas are smaller and would be deemed non-surgical in general practice. However, the data of Lagman et al., suggest that these lipomas may benefit from either medical therapies or early surgical resections. The advantages of early surgery are maximal resection, decreased surgical morbidity, and improved symptom relief 3).

Case series

2014

Of 15 patients with CPA lipomas, six were female and nine were male, with an average age at presentation of 50.2 years (range, 31.7-76.4 yr) and an average follow-up time of 51.7 months (range, 6-216 mo). The lipomas were unilateral in all cases, nine on the right (60%) and six on the left (40%) side. None of the lipomas increased in size. All patients were treated conservatively. Sensorineural hearing loss was the main presenting symptom (80%) followed by tinnitus (46.7%) and vertigo (20%). None of the patients suffered from facial nerve dysfunction. There was no correlation between weight gain and tumor growth.

CPA lipomas can be diagnosed accurately with appropriate magnetic resonance imaging techniques and be managed conservatively with safety. Cochleovestibular are the most common presenting symptoms, whereas facial nerve involvement is rare. CPA lipomas do not tend to grow and can be monitored on a less regular basis 4).

2013

Between 1996 and 2012, 15 patients were diagnosed with a CPA or IAC lipoma at the authors’ institution and were included in the analysis. The mean duration of radiological and clinical follow-up was 3.4 years and 5.1 years, respectively. Eight lesions were confined to the IAC, while seven involved the CPA. The median tumor size at diagnosis was 7.2 mm; one patient demonstrated tumor growth on serial MRI while the remaining subjects did not have radiological progression. The most common presenting symptoms were sensorineural hearing loss (40%) and tinnitus (33%); five patients were diagnosed after incidental discovery on MRI. Fourteen patients were managed with observation, while one subject underwent subtotal resection. None of the observed patients reported worsening symptoms at last follow-up.

While rare, lipomas should be included in the differential diagnosis of CPA and IAC lesions. Owing to a generally benign clinical course and high morbidity associated with resection, microsurgery should only be considered in cases of definite tumor enlargement with intractable symptoms from mass effect. Careful radiological evaluation is critical for establishing an accurate diagnosis in order to prevent unnecessary morbidity associated with resection 5).

2006

A healthy 42-year-old woman who presented with left-sided hearing loss and facial synkinesis. T1-weighted magnetic resonance imaging revealed an enhancing lesion of the left CPA with no signal on fat suppression sequences. Despite conservative therapy, the patient developed progressive hemifacial spasm, and a suboccipital craniotomy approach was used to debulk the tumor, which encased cranial nerves V, VII, VIII, IX, X, and XI. Surgical histopathology demonstrated mature adipocytes, consistent with lipoma. Two years after surgery, the patient remains free of facial nerve symptoms. Cerebellopontine angle lipomas are rare lesions of the skull base and are reliably diagnosed with T1-weighted and fat suppression magnetic resonance sequences, which we recommend in the routine radiologic workup of CPA tumors. Accurate preoperative diagnosis is crucial because most CPA lipomas should be managed conservatively. Partial surgical resection is indicated only to alleviate intractable cranial neuropathies or relieve brainstem compression 6).

2002

Tankéré et al., report four new cases of CPA lipomas diagnosed in the Department of Otorhinolaryngology-Head and Neck Surgery of Hôpital Pitié-Salpêtrière and review 94 cases reported previously in the literature.

Lipomas represented 0.14% of CPA and internal acoustic meatus tumors. Localization was on the left side in 59.9%, on the right side in 37%, and bilateral in 3.1% of the patients. The diagnosis was confirmed radiologically in 33 of 98 patients, surgically in 60 patients, and by autopsy in 5 patients. The most frequent associated symptoms were of cochleovestibular origin, such as hearing loss (62.2%), dizziness (43.3%), and unilateral tinnitus (42.2%). Other associated symptoms involved the facial nerve (9%) or the trigeminal nerve (14.4%). Complete resection was performed in only 32.8% of the patients with frequent cranial nerve involvement. Frequent cranial nerve involvement was seen in 95.4% of all patients. After surgery, patient symptomatology was unchanged in 9.2% of the patients, and 50% were improved; however, new postoperative deficits occurred in two-thirds of the patients. Overall, 72.2% of the patients experienced new postoperative deficits such as hearing loss (64.8%). Preservation of hearing was possible in only 26% of the patients. Only 18% of patients were improved after surgery without any new postoperative deficits.

Preoperative diagnosis of internal acoustic meatus/CPA lipomas is based on magnetic resonance imaging. The aim of surgery in these cases is not tumor removal but cranial nerve decompression or vestibular transection, and surgery is performed only in patients with disabling and uncontrolled symptoms 7).

1998

17 IAC/CPA lipomas, bringing the total number of documented cases to 84 in 1998. There appears to be a nearly 2:1 male to female predominance. Sixty percent were left-sided lesions, and three were bilateral. Hearing loss, dizziness, and tinnitus were the most common presenting symptoms. Surgical resection was performed in 52 (62%) of these lesions; however, total tumor removal was accomplished in only 17 (33%), which is most likely because of the fact that these tumors tend to have a poorly defined matrix and a dense adherence to neurovascular structures. Sixty-eight percent of patients experienced a new deficit postoperatively, 11% were unchanged, and only 19% improved with no new deficit. Only one documented case of tumor growth was identified; however, the reported follow-up was short (average, less than 3 years).

With the magnetic resonance imaging techniques now available, lipomas can be reliably differentiated from other masses within the CPA and IAC, so histopathologic diagnosis is rarely necessary. Because of the potential for significant morbidity with resection of these lesions, we believe that conservative follow-up is the best treatment option for patients with these rare lesions. Surgery is indicated only when significant progressive or disabling symptoms are present 8).

Case reports

2012

A 5-year-old boy was evaluated for recurrent primary generalized seizures of 20 days duration. He had preceding headache, vomiting for which he was subjected to a Magnetic resonance imaging (MRI) scan of the brain. Imaging studies revealed a hyperintense mass in the right CPA suggestive of lipoma/epidermoid. He was referred to us for further management.

Basic routine blood investigations were essentially normal. His vital parameters were stable. He was conscious, oriented, and obeying commands. Child was active and had no motor/sensory/cranial nerve deficits. Plantars were bilaterally flexor with normal deep tendon reflexes. MR imaging has now achieved a very high sensitivity and specificity for detecting lipomas. On T1-weighted MR images, lipomas typically appear hyperintense compared with brain tissue and hyperintense on T2-weighted MR images. MRI scan of the brain was done and the findings is given below.

Multiplanar, multisequences, MR imaging, including SE T1 axial, flair axial, FSE T2 axial were done. Postcontrast T1-weighted multiplanar sequences were also performed.

A 17mm (trans) ×15mm (AP) × 15mm (CC) well-encapsulated mass lesion noted in the right CP angle which was hyperintense on T1, T2, and FLAIR with inversion on fat suppression sequence. The lesion was situated inferior to the right Vth nerve and indenting upon right lower pons and medulla. The right VIIth and VIIIth nerves and superior cerebellar artery were encased by the lesion. No evidence of tumor extension into IAC was noted. There was neither significant shift nor hydrocephalus. Right cerebello pontine angle tumor–lipoma/epidermoid.

A right retro sigmoid suboccipital approach was chosen to expose the tumor. The lesion was extra-axial, yellowish and surrounding the seventh and eighth nerve complex. Branches of the AICA were embedded in the tumor. The lesion was partially decompressed. Neurovascular structures were preserved. There were no postoperative deficits.

Histopathological evaluation revealed it to be lipoma-right CP angle

These tumors can cause symptoms related to the VIII nerve involvement, such as hearing loss, tinnitus, and vertigo. However, trigeminal symptoms such as neuralgia, paresthesia or headache, can also occur with CPA lipomas extending to the trigeminal cisterns.

This patient presented with headache, and seizures. Neuroimaging revealed a hypodense mass in the right CPA suggestive of lipoma/epidermoid. He underwent surgical exploration and decompression of the tumor. Histopathology confirmed it as lipoma 9).

2009

A 13-year-old female patient was evaluated due to a 1-year history of headache and hearing loss. The physical examination was unremarkable. The audiometric evaluation demonstrated a discrete sensorineural hearing loss on the right side. The CT scan revealed a markedly hypodense non-enhancing mass in the right CPA. The MR imaging showed a lesion measuring 2.1 × 2.0 × 1.7 cm in the right CPA cistern. The mass was hyperintense on T1-weighted images and isointense with hypointense halo (chemical-shift) on T2-weighted images, with very low signal on T1-weighted images with fat suppression (Figs 1 and 2). The VII and VIII cranial nerves were seen as linear images with low signal inside the CPA mass. The diagnosis of CPA lipoma was suggested and the surgical treatment was chosen once the patient was young and the chance of lesion growing and future complications was considerable. A craniotomy with posterior fossa approach was performed, the lesion was partially removed, and the histological examination confirmed the diagnosis of lipoma. Six months after the surgery the patient remains asymptomatic. The parent signed the informed consent agreeing with the study.

Case 2

A 35-year-old woman presented with a six-month history of vertigo, without significant abnormalities on physical examination. A CT scan revealed a left-sided hypodense non-enhancing CPA mass. The MR imaging showed a left CPA cistern hyperintense lesion on T1-wheighted images and isointense with hypointense halo (chemical-shift) on T2-weighted images, measuring 1.4 × 1.3 cm and showing no enhancement after contrast administration (Fig 3). The diagnosis of CPA lipoma was suggested and the patient was managed conservatively. The symptoms were controlled with medical therapy. The follow-up MR imaging performed one year later showed no significant modifications 10).

1997

The case of an extensive lipoma of the cerebellopontine angle (CPA) represents 0.05% of all CPA tumors operated on in a department from 1978 to 1996. The lipoma constitutes an important differential diagnosis because the clinical management differs significantly from other CPA lesions. The clinical presentation and management of the presented case are analyzed in comparison to all previously described cases of CPA lipomas. The etiology and the radiological features of CPA lipomas are reviewed and discussed. CPA lipomas are maldevelopmental lesions that may cause slowly progressive symptoms. Neuroradiology enables a reliable preoperative diagnosis. Attempts of complete lipoma resection usually result in severe neurological deficits. Therefore, we recommend a conservative approach in managing these patients. Limited surgery is indicated if the patient has an associated vascular compression syndrome or suffers from disabling vertigo 11).

1994

Two patients with cerebellopontine angle (CPA) lipoma were studied. They were submitted to surgical treatment. Available literature was reviewed and 29 cases with same lesion were identified which had been treated by surgery. Clinical manifestations, possibility of diagnostic methods, surgical indications and treatment strategies are discussed. Attention is called to the peculiarities of CPA lipomas and the doubtful validity of attempting complete excision in all cases12).


1) Bonneville F, Sarrazin JL, Marsot-Dupuch K, Iffenecker C, Cordoliani YS, Doyon D, Bonneville JF. Unusual lesions of the cerebellopontine angle: a segmental approach. Radiographics. 2001 Mar-Apr;21(2):419-38. PubMed PMID: 11259705.
2) , 11) Schuhmann MU, Lüdemann WO, Schreiber H, Samii M. Cerebellopontine angle lipoma: a rare differential diagnosis. Skull Base Surg. 1997;7(4):199-205. PubMed PMID: 17171031; PubMed Central PMCID: PMC1656654.
3) Lagman C, Voth BL, Chung LK, Bui TT, Lee SJ, Barnette NE, Gopen Q, Yang I. Evaluating the utility of a scoring system for lipomas of the cerebellopontine angle. Acta Neurochir (Wien). 2017 Jan 21. doi: 10.1007/s00701-017-3076-5. [Epub ahead of print] PubMed PMID: 28110401.
4) Kontorinis G, Freeman SR, Potter G, Rutherford SA, Siripurapu R, King AT, Lloyd SK. Management of cerebellopontine angle lipomas: need for long-term radiologic surveillance? Otol Neurotol. 2014 Jun;35(5):e163-8. doi: 10.1097/MAO.0000000000000395. PubMed PMID: 24691513.
5) White JR, Carlson ML, Van Gompel JJ, Neff BA, Driscoll CL, Lane JI, Link MJ. Lipomas of the cerebellopontine angle and internal auditory canal: Primum Non Nocere. Laryngoscope. 2013 Jun;123(6):1531-6. doi: 10.1002/lary.23882. PubMed PMID: 23401141.
6) Brodsky JR, Smith TW, Litofsky S, Lee DJ. Lipoma of the cerebellopontine angle. Am J Otolaryngol. 2006 Jul-Aug;27(4):271-4. PubMed PMID: 16798407.
7) Tankéré F, Vitte E, Martin-Duverneuil N, Soudant J. Cerebellopontine angle lipomas: report of four cases and review of the literature. Neurosurgery. 2002 Mar;50(3):626-31; discussion 631-2. Review. PubMed PMID: 11841733.
8) Bigelow DC, Eisen MD, Smith PG, Yousem DM, Levine RS, Jackler RK, Kennedy DW, Kotapka MJ. Lipomas of the internal auditory canal and cerebellopontine angle. Laryngoscope. 1998 Oct;108(10):1459-69. Review. PubMed PMID: 9778284.
9) Venkataramana N, Rao SA, Naik AL, Chaitanya K, Murthy P. Cerebello pontine angle lipoma in a child. J Pediatr Neurosci. 2012 Jan;7(1):75-7. doi: 10.4103/1817-1745.97635. PubMed PMID: 22837790; PubMed Central PMCID: PMC3401666.
10) Borges RS, Brito CC, Carvalho GA, Domingues RC, Gasparetto EL. Cerebellopontine angle lipomas: magnetic resonance imaging findings in two cases. Arq Neuropsiquiatr. 2009 Jun;67(2B):496-8. PubMed PMID: 19623450.
12) Ferreira MP, Ferreira NP, Lenhardt R. Lipoma of the cerebellopontine angle. Case reports and literature review. Arq Neuropsiquiatr. 1994 Mar;52(1):58-63. Review. PubMed PMID: 8002809.

Update: Craniopharyngioma malignant transformation

Epidemiology

Sofela et al., conducted in 2014 conducted a PUBMED, SCOPUS, OVID SP, and INFORMA search with a combination of key words: craniopharyngioma, malignancy, transformation, neoplasm, radiation therapy, and anaplastic. They identified 23 cases relevant to our study.

Median age at the time of diagnosis of malignant craniopharyngiomas was 31 years (range, 10-66 years); 52.6% of the patients were female. Histologically, the most common tumor types were squamous cell carcinoma (80.96%), with adamantinomatous cell type being the most common morphology (89.47%).

Sofela et al., found that 21.7% of the cases were diagnosed as malignant craniopharyngioma at first biopsy. Of the rest, the median time from initial benign diagnosis to MT was 8.5 years (range, 3-55 years). Median overall survival after MT was 6 months (range, 2 weeks-5 years). Using the Spearman rank correlation, we found no correlation between the use of radiation therapy (correlation coefficient, -0.25; P < .05) or its dosage (correlation coefficient, -0.26; P < .05) and MT 2).

Pathogenesis

The exact cause and pathogenesis of this MT are unknown, although the literature has suggested a possible correlation with radiotherapy 3).

Radiation therapy and p53 mutations could be involved in malignant transformation in craniopharyngioma 4).

Histology

It assumes varied histologic appearances, usually after multiple recurrences and radiation therapy, and has a near uniformly fatal outcome. De novo malignancy in odontogenic tumors of the sella is even more unusual, but also has an ominous prognosis 5).

Outcome

Malignant craniopharyngiomas are associated with a poor prognosis. MTs occur years after the initial benign craniopharyngioma diagnosis and are associated with multiple benign craniopharyngioma recurrence. Results also show that, contrary to widespread belief, there is a poor correlation between radiotherapy and MT 6).

Case reports

2017

Jeong et al., report the case of a 26-year-old male patient who underwent suprasellar mass excision via an interhemispheric transcallosal approach. Histopathological examination indicated that the craniopharyngioma was of the adamantinomatous subtype. The patient received postoperative medical treatment for endocrine dysfunction and diabetes mellitus without radiation treatment. Two years after the operation, he presented with progressive visual disturbance and altered mentality. Magnetic resonance imaging revealed a huge mass in the suprasellar cistern and third ventricle. He underwent a second operation via the same approach. The histopathological examination showed an adamantinomatous craniopharyngioma with sheets of solid proliferation in a spindled pattern, indicating malignant transformation 7).

2015

A 29-year-old male patient was admitted into hospital with the main complaint of progressive visual disturbance. Both CT SCAN and MRI demonstrated a cystic-solid contrast-enhancing sellar-suprasellar mass with obvious calcification. Histopathological examination of the first resected specimen showed a typical appearance of adamantinomatous craniopharyngioma. The patient received gamma knife therapy after his first operation because of partial tumor removal. He experienced two relapses in the subsequent 2 years, for which only surgical resection was performed. The later histopathology presented malignant appearance with tumor cells moderate to severe pleomorphism, hyperchromasia, increased nuclear cytoplastic ratio, high mitotic activity (30/10 high power fields) and focal coagulative necrosis. The patient died 9 months after identification of histologic malignancy. Clinical and histopathological features, biological behavior of one case of malignant craniopharyngioma were discussed, with a brief review of the relevant literature 8).

2014

Malignant transformation of craniopharyngioma in an infradiaphragmatic case 9).

2011

A 66-year-old female who presented with visual disturbance and radiological evidence of a sellar and suprasellar tumor. The patient underwent transsphenoidal biopsy followed by pterional craniotomy with partial tumor removal. Histological diagnosis documented a malignant adamantinomatous type craniopharyngioma. The patient received adjuvant radiotherapy with a significant tumor reduction. She remained in good clinical conditions for 10 months; she deteriorated and died, due to tumor progression, 15 months after diagnosis.

This is the first case of de novo malignant craniopharyngioma with significant follow-up 10).


Gao et al., report a case of ameloblastic carcinoma arising from a previously benign craniopharyngioma in a 42-year-old woman. The patient was diagnosed with craniopharyngioma in August 2004 and underwent surgical resection of a typical craniopharyngioma, the pathological result was craniopharyngioma, papillary and adamantinomatous types. During the subsequent 5 years, this patient experienced two recurrences, for which surgical resections were performed without radiotherapy. The last two pathologic diagnoses were malignant craniopharyngiomas and there was more apparent sign of malignancy in the third pathologic section 11).

2010

Aquilina et al., describe 2 additional pediatric cases. Treatment in both of these cases consisted of multiple resections and external beam radiation therapy (EBRT). Malignant transformation occurred 7 and 8 years after EBRT. The authors also review another 6 cases in adults. A possible causative association with radiation therapy is discussed. As radiation is currently an important option in the management of craniopharyngiomas, this association requires further study 12).


A 32-year-old man presented with malignant craniopharyngioma associated with moyamoya syndrome manifesting as right visual disturbance. Magnetic resonance (MR) imaging revealed a parasellar mass lesion diagnosed as adamantinomatous craniopharyngioma. He underwent three surgical procedures and repeated courses of radiotherapy, and was able to resume his daily life. MR imaging demonstrated tumor regrowth and bilateral occlusions of the internal carotid arteries (ICAs) with basal moyamoya phenomenon, which might have been induced by irradiation and/or tumor compression, 10 years after the initial manifestations. Sufficient debulking was safely achieved via the transsphenoidal route and histological examination revealed squamous cell carcinoma, indicating malignant transformation of craniopharyngioma. The tumor relapsed after only one month, so transsphenoidal tumor debulking was tried again. However, the postoperative course was unfavorable because of intraoperative bleeding from the right ICA. Malignant transformation of craniopharyngioma may be included in moyamoya syndrome. The treatment strategy should be carefully considered in such a complicated situation 13).


Ishida et al.,report a case of malignant transformation in craniopharyngioma after radiation therapy.

Histopathological and immunohistochemical analyses were carried out for specimens of the suprasellar tumor (from three resections, with the third surgery performed after radiation therapy).

The resected tumors from the first and second surgeries comprised islands of loosely cohesive aggregates of epithelial cells, so-called stellate reticulum. At the periphery of the nests, palisaded columnar epithelium was observed. Wet keratins were scattered, and few mitotic figures were seen. The third surgical specimen was composed of irregular large nests of basaloid cells that had large, round to oval nuclei with prominent nucleoli, and mitotic figures were frequently seen (21/10 high power fields). In the center of the nests, eosinophilic ghost cells, resembling wet keratin, were observed. Accordingly, the diagnosis of malignant transformation in craniopharyngioma was made. Immunohistochemical studies revealed that the p53 protein was over-expressed in the malignant component, whereas its expression was much lower in the benign component.

Similar to the ten previously reported cases of malignant transformation in craniopharyngioma, the present case occurred after radiation therapy. p53 protein overexpression was also observed in the earlier cases of malignant craniopharyngioma as well as in the present case (6/6 cases). They concluded that radiation therapy and p53 mutations could be involved in malignant transformation in craniopharyngioma 14).

2009

A case of malignant craniopharyngioma in a 46-year-old woman presenting clinically with visual disturbance and bifrontal headache is reported. Histopathologic examination of the suprasellar mass showed a lesion characterized by nests of epithelial cells with a basaloid appearance, round-to-oval nuclei, moderate pleomorphism, hyperchromasia, increased nuclear cytoplastic ratio and high mitotic activity. Immunohistochemically, the tumor cells were positive for Ki-67 (44.3%), p53 (98%), and p63 (100%), but negative for estrogen and progesterone receptors 15).

2007

Rodriguez et al., report 3 patients with craniopharyngiomas exhibiting histologic malignancy, 2 of which received radiation therapy before its appearance. Hematoxylin and eosin-stained slides and selected immunohistochemical stains were reviewed in all cases. Microvessel density analysis was performed in case 2. The patients included 2 men and 1 woman, age 14, 31, and 58 years at presentation, respectively. All patients expired 3 months to 9 years after first resection and 3 to 9 months after identification of histologic malignancy. The latter developed after multiple recurrences and radiation therapy in 2 cases, but seemed to arise de novo in 1 case resembling odontogenic ghost cell carcinoma and lacking any definite low-grade craniopharyngioma precursor. The malignant component of the other 2 cases resembled squamous cell carcinoma and low-grade myoepithelial carcinoma, respectively. The MIB-1 labeling index was markedly increased in the malignant component in comparison with the low-grade precursor 16).

2006

Malignant transformation of craniopharyngioma: a case report 17).

2004

A 21-year-old woman, who developed a malignant tumour arising from a craniopharyngioma 14 years after the original diagnosis. The remarkable response of this malignant tumour ex-craniopharyngioma to cis-platin based chemotherapy, together with other midline tumour characteristics of craniopharyngioma, raise the question as to whether craniopharyngioma should any longer be separately considered from suprasellar germ cell tumour 18).

2000

Kristopaitis et al., describe a case of squamous cell carcinoma arising in a previously benign craniopharyngioma in a 42-year-old woman. The patient was diagnosed with craniopharyngioma in 1982; during the subsequent 15 years she experienced 7 tumor recurrences, for which surgical resections and 3 courses of radiotherapy were performed. In 1998, the tumor recurred with involvement of the nasal cavity and sphenoid and ethmoid sinuses. Histologic evaluation revealed foci of typical adamantinomatous craniopharyngioma associated with a moderately differentiated squamous cell carcinoma. The transition of typical craniopharyngioma to squamous cell carcinoma was well demonstrated, suggesting that carcinoma arose from the underlying craniopharyngioma. Radiation may have been a contributing factor to carcinogenesis in this case 19).

1999

Virik et al., report a further case of malignant transformation in recurrent craniopharyngioma following radiotherapy 20).

1989

Two cases of a craniopharyngioma with malignant transformation are reported. Case 1 involved a 3-year-old male who had received a partial resection and radiotherapy for a suprasellar tumor. Histologically, a biopsy specimen showed craniopharyngioma. Eight years later, the child died of an intracerebral and nasopharyngeal invasion of the recurrent tumor. Case 2 involved a 9-year-old male who initially had been diagnosed as having a craniopharyngioma in the suprasellar region. Five years after the first operation, he died from growth of the tumor in spite of radiotherapy and a partial resection. The pathological examinations of these two cases showed an apparent transition of the craniopharyngioma into a squamous cell carcinoma 21).

1988

A 49-year-old woman presented with recurrence of a suprasellar craniopharyngioma diagnosed 35 years previously. The patient had been treated surgically for recurrence on five occasions. Radiation therapy had been administered 7 years before the final presentation. Tissue obtained from the fifth operation revealed malignant degeneration in a typical craniopharyngioma 22).

1987

Akachi et al., report a rare case of a 10-year-old girl with craniopharyngioma which showed malignant change after the first operation and irradiation. In June 1981, the patient complained of headache, nausea and vomiting. CT revealed obstructive hydrocephalus due to the calcified mass lesion which extended to the third ventricle. In order to alleviate the high intracranial pressure, the right ventriculo-peritoneal shunt was first settled and after that, partial removal of the tumor was performed. The pathological diagnosis of the specimen was typical adamantinomatous type of craniopharyngioma without any findings of malignancy. After this operation irradiation was performed. The tumor almost disappeared and the patient was discharged from the hospital and went to school, showing some signs of panhypopituitarism. In May 1984, she complained of decreased left visual acuity, right temporal anopsia, headache, nausea and vomiting. CT revealed recurrence of the tumor which obstract the foramen of Monro bilaterally. As an emergency measure, the left ventriculo-peritoneal shunt was added and the state of the patient became recovered. In order to improve decreased visual acuity, the tumor located around the optic nerves and over the frontal base was removed in June 1984, resulting in partial improvement of visual acuity bilaterally. The pathological examination of the second specimen showed, in addition to the part of adamantinomatous type of craniopharyngioma which was the same as before, the existence of thick layer of stratified large atypical cells which partially covered the cyst wall and partially invaded into the surrounding tissues. The pathological diagnosis was poorly differentiated squamous cell carcinoma with craniopharyngioma of ‘adamantinoma’ type 23).


1) Akachi K, Takahashi H, Ishijima B, Nakamura Y, Oda M, Takizawa T, Iwamoto M, Kuriyama G, Shizuki K. [Malignant changes in a craniopharyngioma]. No Shinkei Geka. 1987 Aug;15(8):843-8. Japanese. PubMed PMID: 3431651.
2) , 6) Sofela AA, Hettige S, Curran O, Bassi S. Malignant transformation in craniopharyngiomas. Neurosurgery. 2014 Sep;75(3):306-14; discussion 314. doi: 10.1227/NEU.0000000000000380. Review. PubMed PMID: 24978859.
3) Virik K, Turner J, Garrick R, Sheehy JP. Malignant transformation of craniopharyngioma. J Clin Neurosci. 1999 Nov;6(6):527-30. PubMed PMID: 18639199.
4) , 14) Ishida M, Hotta M, Tsukamura A, Taga T, Kato H, Ohta S, Takeuchi Y, Nakasu S, Okabe H. Malignant transformation in craniopharyngioma after radiation therapy: a case report and review of the literature. Clin Neuropathol. 2010 Jan-Feb;29(1):2-8. Review. PubMed PMID: 20040326.
5) , 16) Rodriguez FJ, Scheithauer BW, Tsunoda S, Kovacs K, Vidal S, Piepgras DG. The spectrum of malignancy in craniopharyngioma. Am J Surg Pathol. 2007 Jul;31(7):1020-8. PubMed PMID: 17592268.
7) Jeong TS, Yee GT, Kim NR. Malignant Transformation of Craniopharyngioma without Radiation Therapy: Case Report and Review of the Literature. J Korean Neurosurg Soc. 2017 Jan 1;60(1):108-113. doi: 10.3340/jkns.2015.0707.022. PubMed PMID: 28061501.
8) Wang W, Chen XD, Bai HM, Liao QL, Dai XJ, Peng DY, Cao HX. Malignant transformation of craniopharyngioma with detailed follow-up. Neuropathology. 2015 Feb;35(1):50-5. doi: 10.1111/neup.12142. PubMed PMID: 25112406.
9) Lu Y, Qi S, Peng J, Pan J, Zhang X. Malignant transformation of craniopharyngioma in an infradiaphragmatic case. Chin Med J (Engl). 2014;127(17):3187-8. PubMed PMID: 25189968.
10) Lauriola L, Doglietto F, Novello M, Signorelli F, Montano N, Pallini R, Maira G. De novo malignant craniopharyngioma: case report and literature review. J Neurooncol. 2011 Jun;103(2):381-6. doi: 10.1007/s11060-010-0382-7. Review. PubMed PMID: 20814809.
11) Gao S, Shi X, Wang Y, Qian H, Liu C. Malignant transformation of craniopharyngioma: case report and review of the literature. J Neurooncol. 2011 Jul;103(3):719-25. doi: 10.1007/s11060-010-0407-2. Review. PubMed PMID: 20872276.
12) Aquilina K, Merchant TE, Rodriguez-Galindo C, Ellison DW, Sanford RA, Boop FA. Malignant transformation of irradiated craniopharyngioma in children: report of 2 cases. J Neurosurg Pediatr. 2010 Feb;5(2):155-61. doi: 10.3171/2009.9.PEDS09257. PubMed PMID: 20121363.
13) Ujifuku K, Matsuo T, Takeshita T, Hayashi Y, Hayashi K, Kitagawa N, Hayashi T, Suyama K, Nagata I. Malignant transformation of craniopharyngioma associated with moyamoya syndrome. Neurol Med Chir (Tokyo). 2010;50(7):599-603. PubMed PMID: 20671391.
15) Boongird A, Laothamatas J, Larbcharoensub N, Phudhichareonrat S. Malignant craniopharyngioma; case report and review of the literature. Neuropathology. 2009 Oct;29(5):591-6. doi: 10.1111/j.1440-1789.2008.00986.x. Review. PubMed PMID: 19077042.
17) Yue Y, Da JP. [Malignant transformation of craniopharyngioma: a case report]. Zhonghua Bing Li Xue Za Zhi. 2006 Jul;35(7):439. Chinese. PubMed PMID: 17069689.
18) Plowman PN, Besser GM, Shipley J, Summersgill B, Geddes J, Afshar F. Dramatic response of malignant craniopharyngioma to cis-platin-based chemotherapy. Should craniopharyngioma be considered as a suprasellar ‘germ cell’ tumour? Br J Neurosurg. 2004 Oct;18(5):500-5. PubMed PMID: 15799153.
19) Kristopaitis T, Thomas C, Petruzzelli GJ, Lee JM. Malignant craniopharyngioma. Arch Pathol Lab Med. 2000 Sep;124(9):1356-60. PubMed PMID: 10975938.
20) Virik K, Turner J, Garrick R, Sheehy JP. Malignant transformation of craniopharyngioma. J Clin Neurosci. 1999 Nov;6(6):527-30. PubMed PMID: 18639199.
21) Suzuki F, Konuma I, Matsumoto M, Aoki M, Hayakawa I. [Craniopharyngioma with malignant transformation–a report of two cases]. Gan No Rinsho. 1989 May;35(6):723-8. Review. Japanese. PubMed PMID: 2657129.
22) Nelson GA, Bastian FO, Schlitt M, White RL. Malignant transformation in craniopharyngioma. Neurosurgery. 1988 Feb;22(2):427-9. PubMed PMID: 3352897.
23) Akachi K, Takahashi H, Ishijima B, Nakamura Y, Oda M, Takizawa T, Iwamoto M, Kuriyama G, Shizuki K. [Malignant changes in a craniopharyngioma]. No Shinkei Geka. 1987 Aug;15(8):843-8. Japanese. PubMed PMID: 3431651.

Update: Vernet’s syndrome


In contrast to the majority of classic brainstem syndromes, the interpretation of Schmidt’s syndrome (ipsilateral palsy of the IX, X, XI, and XII cranial nerves with contralateral hemiparesis) and Vernet’s syndrome (ipsilateral palsy of the IX, X, and XI nerves with contralateral hemiparesis) is controversial. They are sometimes addressed as crossed brainstem syndromes but also as syndromes due to multiple cranial nerve lesions without contralateral hemiparesis. In this study, the historic descriptions and recent publications about Schmidt’s and Vernet’s syndromes were reviewed and critically analysed. We conclude that historic descriptions and later publications describe exclusively patients with extracerebral lesions of multiple cranial nerves. “Central” syndromes of Schmidt and Vernet caused by brainstem lesion appear not to exist. An extremely extensive lesion explaining these hypothetical unilateral brainstem syndromes is theoretically possible but, however, was apparently never observed in any of the known unilateral brainstem diseases 1).

Symptoms

Symptoms of this syndrome are consequences of this paresis. As such, in an affected patient, you may find:

dysphonia/hoarseness

soft palate dropping

deviation of the uvula towards the normal side

dysphagia

loss of sensory function from the posterior 1/3 of the tongue

decrease in the parotid gland secretion

loss of gag reflex

sternocleidomastoid and trapezius muscles paresis.

Etiology

A variety of neoplasms, vascular insults, infections, and trauma have been reported to cause JFS 2).


The causes of Vernet syndrome are primary tumors such as Glomus jugulare tumors (most frequently), meningioma, vestibular schwannoma, cerebellopontine angle metastases, inflammation such as meningitis and malignant otitis externa, and sarcoidosis, Guillain-Barre syndrome 3).

Trauma 4) 5).

Cholesteatoma (very rare) 6).

Obstruction of the jugular foramen due to bone diseases 7).

Varicella-zoster virus 8).

Giant cell arteritis 9) 10).

Internal jugular vein thrombosis 11).

After carotid endarterectomy 12).

Large mycotic aneurysm of the extracranial internal carotid artery after acute otitis media 13).

Systemic erythematous lupus 14).


1) Krasnianski M, Neudecker S, Zierz S. [The Schmidt and Vernet classical syndrome. Alternating brain stem syndromes that do not exist?]. Nervenarzt. 2003 Dec;74(12):1150-4. Review. German. PubMed PMID: 14647918.
2) Robbins KT, Fenton RS. Jugular foramen syndrome. J Otolaryngol. 1980 Dec;9(6):505-16. PubMed PMID: 7206037.
3) Ha SW, Kim JK, Kang SJ, Kim MJ, Yoo BG, Kim KS, et al. A case of Vernet’s syndrome caused by non-specific focal inflammation of the neck. J Korean Soc Clin Neurophysiol. 2007;9:81–84.
4) , 5) Kim HS, Ko K. Penetrating trauma of the posterior fossa resulting in Vernet’s syndrome and internuclear ophthalmoplegia. J Trauma. 1996 Apr;40(4):647-9. PubMed PMID: 8614050.
6) Erol FS, Kaplan M, Kavakli A, Ozveren MF. Jugular foramen syndrome caused by choleastatoma. Clin Neurol Neurosurg. 2005 Jun;107(4):342-6. PubMed PMID: 15885397.
7) Erol FS, Kaplan M, Kavakli A, Ozveren MF.Jugular foramen syndrome caused by choleastatoma. Clin Neurol Neurosurg. 2005 Jun;107(4):342-6.
8) Jo YR, Chung CW, Lee JS, Park HJ. Vernet syndrome by varicella-zoster virus. Ann Rehabil Med. 2013 Jun;37(3):449-52. doi: 10.5535/arm.2013.37.3.449. PubMed PMID: 23869347; PubMed Central PMCID: PMC3713306.
9) Jeret JS. Giant cell arteritis and Vernet’s syndrome. Neurology. 1999 Feb;52(3):677. PubMed PMID: 10025824.
10) Cherin P, De Gennes C, Bletry O, Lamas A, Launay M, Dubs A, Godeau P. Ischemic Vernet’s syndrome in giant cell arteritis: first two cases. Am J Med. 1992 Sep;93(3):349-52. PubMed PMID: 1524092.
11) Shima K, Iwasa K, Yoshita M, Yamada M. Vernet’s syndrome induced by internal jugular vein thrombosis. J Neurol Neurosurg Psychiatry. 2016 Nov;87(11):1252-1253. doi: 10.1136/jnnp-2015-311665. PubMed PMID: 26354943.
12) Tamaki T, Node Y, Saitoum N, Saigusa H, Yamazaki M, Morita A. Vernet’s syndrome after carotid endarterectomy. Perspect Vasc Surg Endovasc Ther. 2013 Dec;25(3-4):65-8. doi: 10.1177/1531003514525476. PubMed PMID: 24625858.
13) Amano M, Ishikawa E, Kujiraoka Y, Watanabe S, Ashizawa K, Oguni E, Saito A, Nakai Y, Ikeda H, Abe T, Uekusa Y, Matsumura A. Vernet’s syndrome caused by large mycotic aneurysm of the extracranial internal carotid artery after acute otitis media–case report. Neurol Med Chir (Tokyo). 2010 Jan;50(1):45-8. PubMed PMID: 20098025.
14) Leache Pueyo JJ, Campos del Alamo MA, Gil Paraíso P, Ortiz García A. [Vernet’s syndrome as an early manifestation of systemic erythematous lupus]. An Otorrinolaringol Ibero Am. 1997;24(2):135-41. Spanish. PubMed PMID: 9199109.

Genome-wide analysis of differentially expressed lncRNAs and mRNAs in primary gonadotrophin adenomas by RNA-seq

Long noncoding RNAs (lncRNAs) have received increased research interest owing to their participation via distinct mechanisms in the biological processes of clinically nonfunctioning pituitary adenomas. However, changes in the expression of lncRNAs in gonadotropin secreting pituitary adenoma, which is the most common nonfunctional pituitary adenomas, have not yet been reported.

Li et al., performed a genome-wide analysis of lncRNAs and mRNAs obtained from gonadotrophin adenoma patients’ samples and normal pituitary tissues using RNA-seq. The differentially expressed lncRNAs and mRNAs were identified using fold-change filtering.

They identified 839 lncRNAs and 1015 mRNAs as differentially expressed. Gene Ontology analysis indicated that the biological functions of differentially expressed mRNAs were related to transcription regulator activity and basic metabolic processes. Ingenuity Pathway Analysis was performed to identify 64 canonical pathways that were significantly enriched in the tumor samples. Furthermore, to investigate the potential regulatory roles of the differentially expressed lncRNAs on the mRNAs, they constructed general co-expression networks for 100 coding and 577 non-coding genes that showed significantly correlated expression patterns in tumor cohort. In particular, they built a special sub-network of co-expression involving 186 lncRNAs interacting with 15 key coding genes of the mTOR pathway, which might promote the pathogenesis of gonadotrophin tumor. This is the first study to explore the patterns of genome-wide lncRNAs expression and co-expression with mRNAs, which might contribute to the molecular pathogenesis of gonadotrophin adenoma 1).

Diagnosis

Gonadotroph adenomas are difficult to diagnose because they are usually non-secreting, or they secrete biologically inactive peptides with no clinical effects, and they classically grow silently until neurological symptoms develop.

Clinical signs or symptoms of gonadotropin hypersecretion are very rarely reported, involving a few premenopausal women with ovarian hyperstimulation syndrome and men with macro- orchids.

A large proportion of the adult patients undergoing surgery for clinically nonfunctioning pituitary adenoma had a silent gonadotroph adenoma: the definitive diagnosis can only be established from a positive FSH/LH immunoreactivity.

Most are endocrinologically silent, and neurological symptoms due to their large volume are the first clinical signs; they are rarely reported to be secreting gonadotropins, this usually occurring in cases with clinical endocrine findings.

Among gonadotropinomas, female gender (77%), macroadenoma (84%), young age at diagnosis (28 ± 12 years), delay from first symptoms to diagnosis (up to 15 years), and ovarian cysts/menstrual disorders in females or macro-orchidism in males were the foremost clinical and neuroimaging features.

Male gonadotropin-secreting pituitary adenomas may have a variable clinical expression secondary to testosterone excess. Somatostatin analogs, dopamine agonists or temozolomide may have a role that needs to be assessed case by case.

Treatment

Gonadotrophinomas are often treated surgically because they are unresponsive to conventional medical therapies. Temozolomide was recently recommended for non-responder aggressive pituitary adenoma management 2).


1) Li J, Li C, Wang J, Song G, Zhao Z, Wang H, Wang W, Li H, Li Z, Miao Y, Li G, Zhang Y. Genome-wide analysis of differentially expressed lncRNAs and mRNAs in primary gonadotrophin adenomas by RNA-seq. Oncotarget. 2016 Dec 15. doi: 10.18632/oncotarget.13948. [Epub ahead of print] PubMed PMID: 27992366.
2) Ceccato F, Occhi G, Regazzo D, Randi ML, Cecchin D, Gardiman MP, Manara R, Lombardi G, Denaro L, Mantero F, Scaroni C. Gonadotropin secreting pituitary adenoma associated with erythrocytosis: case report and literature review. Hormones (Athens). 2014 Jan-Mar;13(1):131-9. PubMed PMID: 24722134.

Update: Geniculate neuralgia

J.Sales-Llopis

Neurosurgery Department, University General Hospital of Alicante, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), Alicante, Spain

Geniculate neuralgia is a pain syndrome associated with the nervus intermedius.

Epidemiology

Fewer than 150 reported cases were published in English between 1932 and 2012 1).

Etiology

The etiology of the condition remains unknown 2).

Symptoms

The pain may also be of gradual onset and of a dull, persistent nature, with occasional sharp, stabbing pain like an electric shock, deep in the ear 3).

Some people have reported additional symptoms during pain attacks:

Salivation

Bitter taste

Tinnitus

Vertigo

Diagnosis

The clinical presentation varies. Non-neuralgic causes of otalgia should always be excluded by a thorough clinical examination, audiological assessment and radiological investigations before making a diagnosis of geniculate neuralgia 4).

Differential diagnosis

Due to the close anatomical proximity, temporomandibular joint (TMJ) pathologies should be included in the differential diagnosis.

Easily confused with trigeminal neuralgia and glossopharyngeal neuralgia. However, nerves intermedius has its characteristic clinical syndroms to be diagnosed.

see Ramsay Hunt syndrome.

Treatment

The treatment has not been established, although it seems reasonable that the therapeutic approaches used in other more common craniofacial neuralgias, such as trigeminal neuralgia, should be effective.

Conservative medical treatment is always the first-line therapy.

Surgical treatment should be offered if medical treatment fails. The two commonest surgical options are transection of the nervus intermedius, and microvascular decompression of the nerve at the nerve root entry zone of the brainstem. However, extracranial intratemporal division of the cutaneous branches of the facial nerve may offer a safer and similarly effective treatment.

The response to medical treatment for this condition varies between individuals. The long-term outcomes of surgery remain unknown because of limited data 5).

Geniculate ganglion section

Rupa et al., postulate that geniculate ganglionectomy may be ineffective as the sole treatment for certain cases of geniculate neuralgia, and that nervus intermedius section may also be required to achieve a more complete deafferentation 6).

Case series

2015

Thirumala et al., analyzed preoperative and postoperative audiogram data and brainstem auditory evoked potentials (BAEPs) from 8 patients with GN who underwent MVD. Differences in pure tone audiometry > 10 dB at frequencies of 0.25, 0.5, 1, 2, 4, and 8 kHz were calculated preoperatively and postoperatively for both the ipsilateral and the contralateral sides. Intraoperative monitoring records were analyzed and compared with the incidence of HFHL, which was defined as a change in pure tone audiometry > 10 dB at frequencies of 4 and 8 kHz.

High-frequency hearing loss occurred after MVD for TGN, GPN, or GN, and the greatest incidence occurred on the ipsilateral side. This hearing loss may be a result of drill-induced noise and/or transient loss of cerebrospinal fluid during the course of the procedure. Changes in intraoperative BAEP waveforms were not useful in predicting HFHL after MVD. Repeated postoperative audiological examinations may be useful in assessing the prognosis of HFHL 7).

2002

Excision of the nervus intermedius and/or of the geniculate ganglion by the middle cranial fossa approach without the production of facial paralysis, in any of 15 cases with geniculate neuralgia is reported. Use of these technique, sometimes in combination with selective section of the Vth cranial nerve, has been successful in relieving the pain of geniculate neuralgia 8).

In 2002 Pulec, review the long-term outcomes in 64 patients who were treated in this manner. Findings indicate that excision of the nervus intermedius and geniculate ganglion can be routinely performed without causing facial paralysis and that it is an effective definitive treatment for intractable geniculate neuralgia 9).

1997

After failing conservative treatment and after undergoing neurologic, otologic, and dental evaluations, 14 patients underwent 20 intracranial procedures consisting of retromastoid craniectomies with microvascular decompression of cranial nerves V, IX, and X with section of the nervus intermedius in most cases.

At operation, vascular compression of the nerves and nervus intermedius was found, which implicated vascular compression as an etiology of this disorder. Initially, 10 of 14 patients had an excellent outcome (71.5%), 3 experienced partial relief (21.5%), and there was 1 failure (7%). Ten patients were available for long-term (> 12 months) follow-up. Of these 10, 3 retained the excellent result (30%), 6 experienced partial relief (60%), and there was 1 failure (10%). Complications included one transient facial paresis, one facial numbness, one paresis of cranial nerves IX and X, one chemical meningitis, two cerebrospinal fluid leaks, and one superficial wound infection. Of those that fell from the excellent to partial category, this usually involved a return of atypical facial pain, but otalgia remained resolved.

Overall, good results (with excellent or partial relief) were found long term for 90% of patients in this series. The authors recommend microvascular decompression of cranial nerves V, IX, and X with nervus intermedius section for the treatment of geniculate neuralgia 10).

Case reports

2014

A case illustration was presented that demonstrates the novel brainstem functional imaging findings for geniculate neuralgia. A 39-year-old man presented with a history of left “deep” ear pain within his ear canal. He noted occasional pain on the left side of his face around the ear. He had been treated with neuropathic pain medications without relief. His wife described suicidal ideations discussed by her husband because of the intense pain.

The patient’s neurologic examination was normal, and otolaryngologic consultation revealed no underlying structural disorder. Anatomic imaging revealed a tortuous vertebral artery-posterior inferior cerebellar artery complex with the posterior inferior cerebellar artery loop impinging on the root entry zone of the nervus intermedius-vestibulocochlear nerve complex and just inferior to the root entry zone of the facial nerve and a small anterior inferior cerebellar artery loop interposed between the cranial nerve VII-VIII complex and the hypoglossal and glossopharyngeal nerves. A left-sided retromastoid craniotomy was performed, and the nervus intermedius was transected. An arterial loop in contact with the lower cranial nerves at the level of the brainstem was mobilized with a polytetrafluoroethylene implant.

The patient indicated complete relief of his preoperative pain after surgery. He has remained pain-free with intact hearing and balance 11).

2007

Figueiredo et al., present a case report of a female patient who was successfully managed with pharmacological treatment 12).

1984

A patient had combined otalgia and intractable unilateral facial spasm, relieved by microsurgical vascular decompression of the seventh and eighth cranial nerve complex in the cerebellopontine angle without section of the intermediate nerve. A dolicho-ectatic anterior inferior cerebellar artery compressed the seventh and eighth cranial nerves complex, suggesting that vascular compression of the intermediate nerve or of the sensory portion of the facial nerve may cause geniculate neuralgia. “Tic convulsif” seems to be a combination of geniculate neuralgia and hemifacial spasm. This combination could be due to vascular compression of the sensory and motor components of the facial nerve at their junction with the brainstem 13).


1) , 2) , 4) , 5) Tang IP, Freeman SR, Kontorinis G, Tang MY, Rutherford SA, King AT, Lloyd SK. Geniculate neuralgia: a systematic review. J Laryngol Otol. 2014 May;128(5):394-9. doi: 10.1017/S0022215114000802. Review. PubMed PMID: 24819337.
3) , 8) Pulec JL. Geniculate neuralgia: diagnosis and surgical management. Laryngoscope. 1976 Jul;86(7):955-64. PubMed PMID: 933690.
6) Rupa V, Weider DJ, Glasner S, Saunders RL. Geniculate ganglion: anatomic study with surgical implications. Am J Otol. 1992 Sep;13(5):470-3. PubMed PMID: 1443083.
7) Thirumala P, Meigh K, Dasyam N, Shankar P, Sarma KR, Sarma DR, Habeych M, Crammond D, Balzer J. The incidence of high-frequency hearing loss after microvascular decompression for trigeminal neuralgia, glossopharyngeal neuralgia, or geniculate neuralgia. J Neurosurg. 2015 Dec;123(6):1500-6. doi: 10.3171/2014.10.JNS141101. PubMed PMID: 25932612.
9) Pulec JL. Geniculate neuralgia: long-term results of surgical treatment. Ear Nose Throat J. 2002 Jan;81(1):30-3. Review. PubMed PMID: 11816385.
10) Lovely TJ, Jannetta PJ. Surgical management of geniculate neuralgia. Am J Otol. 1997 Jul;18(4):512-7. PubMed PMID: 9233495.
11) Tubbs RS, Mosier KM, Cohen-Gadol AA. Geniculate neuralgia: clinical, radiologic, and intraoperative correlates. World Neurosurg. 2013 Dec;80(6):e353-7. doi: 10.1016/j.wneu.2012.11.053. PubMed PMID: 23178920.
12) Figueiredo R, Vazquez-Delgado E, Okeson JP, Gay-Escoda C. Nervus intermedius neuralgia: a case report. Cranio. 2007 Jul;25(3):213-7. Review. PubMed PMID: 17696039.
13) Yeh HS, Tew JM Jr. Tic convulsif, the combination of geniculate neuralgia and hemifacial spasm relieved by vascular decompression. Neurology. 1984 May;34(5):682-3. PubMed PMID: 6538661.