Neurosurgery Department, University General Hospital of Alicante, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), Alicante, Spain
Approximately 70% to 80% of cases occur in women 2).
The classification system for tentorial meningiomas proposed by Gazi Yasargil is the most accurate and emphasizes the surgical anatomy.
T1-T3 the lesions on the inner ring or lesions of the incisura – anterior, lateral and posterior. T4 and T8 are intermediate ring lesions with T8 tumors involving the falcotentorial junction. T5-T7 are lesions on the posterior ring, involving the torcular, transverse sinus, and transverse-sigmoid junction respectively 3).
Signs and symptoms of cranial hypertension are the most common findings, followed by cerebellar ataxia, psychiatric disturbances and cranial nerve dysfunction 4).
In all patients with tentorial meningiomas, a contrast-enhanced CT scan and a magnetic resonance (MRI) of the brain should be ordered. The CT scan in axial and coronal views should be carefully evaluated to see the relations of the lesion with the falx and tentorium. The CT images still provide superior bone detail and are invaluable where tumors invade bones 5).
The MRI is more precise on revealing information about tumor localization, extension and its relations. Special attention should be given to where the tumor expands mostly into the two compartments. In fact with, MR and MR angiography (MRA) the size, dominance and collateralization of the transverse sinuses can be recognized. This factor is essential for this kind of approach. We should obtain all possible possible about the transverse sinus status. If infiltration is present, it should be quantified 6).
Is sometimes necessary to obtain additional information about the arterial and venous system. Using the four-vessels angiography we are able to delineate the vascularity of the lesion and its relationship to the various arteries and veins in this area. The circulation supplying the tumor is carefully analyzed in order to plan both endovascular and surgical procedures. The vein of Galen, the internal cerebral veins and the basal vein of Rosenthal should be studied. As well as the superficial venous system, with the patency of the straight sinus, and the collateralization and enlargement of the normally present sinus should also be analyzed.
If the preoperative embolization is effective the surgical procedure become easier 7).
For Cerebral CT venography see Cerebral CT venography in surgical planning for a tentorial meningioma 8)
A 72-year-old male presented with a primary hemangioblastoma of the posterior fossa with unusual dural attachment and meningeal arterial blood supply from the external carotid artery and marginal tentorial artery. Preoperative embolization facilitated complete resection of the tumor with no resultant neurological deficit. Hemangioblastoma must be included in the differential diagnosis of tumors with dural involvement. Preoperative embolization is very useful in such tumors 9).
see Surgical anatomy and approaches 10)
External link: http://neurosurgery.mgh.harvard.edu/images/men29.jpg
A U-shaped or linear incision is made. The preference of the kind of the incision is dictated by the size of the tumor.
The size of the craniotomy is also dictated by the size of the tumor.
Burr holes are placed above and below the transverse sinus and in a majority of the times, the bone over the sinus is drilled away. For the superior and inferior components of the craniotomy the craniotome can be perfectly used after the dura is dissected from the bone.
After the craniotomy, the dura of the occipital lobe and the suboccipital compartment are exposed. The transverse sinus is placed between both compartments. The transverse sinus and its junction with the torcular Herophilli are exposed.
The thulium laser proved to be a useful tool during coagulation, shrinking, and resection of the basal implant of the tumor. Use of the laser made the surgical procedure faster and easier, and no intraoperative bleeding was noted. No side effects were observed 11)
They tend to enclose, displace, or compress the adjacent cranial nerves and vascular structures. Due to their vicinity to crucial neural and vascular structures, they are a surgical challenge.
The first historic attempts at tentorial meningioma removal resulted in high rates of mortality and morbidity. In series published up to 1990, the mortality rate ranged from 14% to 44% 12) 13) 14)15).
Thirty-nine patients with meningiomas of the tentorium underwent stereotactic radiosurgery (SRS) using various Gamma Knife technologies between 1988 and 2010. The most common presenting symptoms were headache, dizziness or disequilibrium, and ataxia.
The median tumor volume was 4.6 cm3 (range 0.5-36.6 cm3) and the median radiation dose to the tumor margin was 14 Gy (range 8.9-18 Gy). The median follow-up period was 41 months (range 6-183 months). At the last imaging follow-up, tumor volumes decreased in 22 patients (57 %), remained stable in 13 patients (33 %), and increased in 4 patients (10 %). The progression free survival after SRS was 97 % at 1 year, and 92 % at 5 years. At the last clinical follow-up, 35 patients (90 %) showed no change in symptoms, 1 patient (2 %) showed improvement of their neurologic symptom, and 3 patients (8 %) demonstrated worsening symptoms. The rate of symptom worsening after SRS was 5 % at 1 year, and 10 % at 5 years. Asymptomatic peritumoral edema after SRS occurred in 2 patients (5 %). Symptomatic adverse radiation effect developed in 2 patients (5 %). SRS for tentorial meningiomas provided long-term effective tumor control and a low risk of radiation related complications 21).
From 1998 to 2005, 30 patients (22 female and 8 male) with tentorial meningiomas were operated. Thirteen patients had tumor restricted to the infratentorial space; 12, to the supratentorial space; and in 5 cases, the tumor involved both compartments. Follow-up ranged from 1 to 8 years. A total of 35 surgical procedures were performed in 30 patients, where 26 procedures were performed through a single approach (2, ITSC; 10, RS; 5, SOIH; 5, ST; and 4, TT); and 9, through combined approaches (7, ITSC/ SOIH; and 2, RS/ST).
Simpson I resection was achieved in 17 patients. Tumors involving both compartments, involving the petrous sinus, and attached to the torcula limited complete resection. Twenty-two out of 30 patients were able to return to their regular life with no or minimal neurological sequelae. Most frequent complications in our series were shunt dependence, CSF fistulae, diffuse brain injury and visual field defects. Overall, our series revealed 3% mortality and 23% morbidity.
Tentorial meningiomas are associated with significant morbidity related to the nervous and vascular structures surrounding the tumor. Partial tumor removal may be necessary in some cases22).
Kaki et al. report the experience and long-term results of twenty patients with tentorial meningiomas who underwent surgical removal between 1987 and 1996. Computed tomography, angiography and magnetic resonance imaging were used as diagnostic tools for planning the surgical procedure. The tumor site was posterolateral in 6 cases (30%), posteromedial in 4 cases (20%), in the tentorium itself in 4 cases (20%), anterolateral in 3 cases (15%), at the apex of tentorial incisura in 2 cases (10%) and at the free border of the tentorial notch in 1 case (5%). Neuroradiologically, 70% of the meningiomas ranged from 1 to 3 cm. Lateral and medial tumors with solely or mainly supratentorial development were approached from above. The approach from below was selected for meningiomas with subtentorial involvement only. In meningiomas with both supra and subtentorial growth, a supratentorial bone flap was combined with a suboccipital craniectomy using a retromastoid incision. Radical surgical removal (Simpson’s grade I and II) was achieved in 80% of the cases. There was no mortality. The follow-up averaged 4 years and revealed that 65% of patients were able to return to their premorbid activity. Complications were mainly postoperative brain oedema, functional deficits, seizures and psychological disorders. Recurrence rate amounted at 6.25% in the group where the tumors were totally removed (16 cases). From this retrospective study, the statistically significant prediction of a good outcome was: duration of symptoms from onset to the operation inferior or equal to 1 year (p < 0.01), good preoperative neurological conditions (Karnofsky scale from 80 to 100) (p < 0.05) and tumor size inferior or equal to 3 cm (p < 0.002) 23).
Olivecrona series included 21 tentorial meningiomas representing 2.5% of all of their intracranial meningiomas. He found in his series 52% of these lesions above the tentorium and 48% below. The transverse sinus was invaded in 52%. In a such way the first attempt to classify the tentorial meningioma was made by him 24).
In the Cushing and Eisenhard’s series of 295 intracranal meningiomas, 11 tumors (3.7%) were attached to the tentorium 25).
A rare case of hemifacial spasm caused by an ipsilateral tentorial meningioma is described. Magnetic resonance imaging showed a huge tumor in the right cerebellar hemisphere, distant to the cerebello-pontine cistern. The facial-vestibulocochlear nerve complex was stretched by the shift of the brainstem and the right cerebello-pontine cistern was effaced. After removing the tumor, the hemifacial spasm resolved completely. We review our case with the pertinent literature regarding the etiological mechanism 26).
Perrini et al. describe a patient with a large paramedian tentorial meningioma associated with acquired Chiari malformation who presented with trigeminal neuralgia TN. Trigeminal pain resolved after gross total tumour resection and postoperative magnetic resonance images disclosed a minimal residual tumour in the torcular region as well as ascent of cerebellar tonsils. In this article, we investigate the physiopathological hypotheses for this unusual association with emphasis on the role of tonsillar prolapse as neuropathological basis of neuropathic pain in this patient 27).
Guan et al. report a spontaneous cerebrospinal fluid rhinorrhea in a patient with tectorial meningioma 28).
Tentorial meningioma on follow-up presenting with sudden deterioration due to intra- and peritumoral hemorrhage 29).
A 45-year-old woman suffering from hemifacial spasm, who dramatically improved after surgical removal of a tentorial paramedic meningioma 30).
Concomitant ectatic posterior communicating artery and tentorial meningioma as a source of oculomotor palsy: case report 31).
Santoro et al. describe the case of patient who underwent subtotal resection of a chromophobe pituitary adenoma at the age of 18 years, who was successively treated by conventional fractionated radiotherapy with gamma rays emitted by a source of 60Co until a total dose of 41 Gy. Over the next 30 years the patient experienced all the known late effects of radiation, including panhypopituitarism, cranial-nerve deficits (II, III and VI), massive radiation necrosis involving the left cerebral hemisphere and causing right hemiparesis and aphasia and, ultimately, an atypical tentorial meningioma with early recurrence after total resection 32).
Secondary syringomyelia disappearing after removal of tectorial meningioma 33).
A 35-year-old right-handed woman presented with a generalized convulsion. Magnetic resonance imaging scans revealed a left medial tentorial meningioma with supratentorial extension at the dominant hemisphere. The main venous drainage route from the ipsilateral temporal lobe was a sphenopetrosal vein.
An operation was performed with the patient in a sitting position, and the tumor was resected totally via the paramedian supracerebellar transtentorial approach without perioperative complications.
The paramedian supracerebellar transtentorial approach is useful for supratentorially located medial tentorial meningiomas without retraction of the temporal lobe and without damage to the vein of Labbé or the sphenopetrosal vein 34).
A 33-year-old male presented with involuntary and inappropriate laughter. Neuroimaging revealed a meningioma ventrolateral to the pons and midbrain, attached to the medial middle tentorium on the left side. The pathological laughter ceased immediately after subtotal removal of the tumor. Pathological laughter may be an early focal sign of a mass compressing ventrolateral brainstem 35).
A 73-year-old female case with tentorial meningioma suffering from pure word deafness is reported. The patient initially presented with hydrocephalus, and was treated with a ventriculo-peritoneal(V-P) shunt. A year after the V-P shunt, she suffered from a symptom of deafness. On admission, her repetition and auditory comprehension were severely impaired, while reading and visual comprehension were almost normal. Auditory brain stem response(ABR) revealed normal latency between wave I and V, while wave VI and VII was disappeared. Middle latency response(MLR) showed no wave peak. On MRI, tentorial meningioma compressed bilateral medial geniculate bodies, but not auditory radiation or temporal lobe. 99mTc-HMPAO single photon emission computed tomography(SPECT) showed hypoperfusion in the left temporal lobe, considered as a diaschisis resulting from the isolation of left temporal lobe from auditory input via bilateral medial geniculate bodies 36).
A 62-year-old woman was evaluated for tinnitis and headache. Magnetic resonance imaging and angiography revealed the coexistence of a tentorial tumor encroaching the junction of the right transverse-sigmoid sinuses, and dural arteriovenous fistulous malformation (AVFM) of the right transverse sinus. AVFM was not manipulated at all during the surgery. The pathology was fibroblastic meningioma. Postoperatively, the dural AVFM completely disappeared on follow-up angiography. The fistulas were occluded also after surgery, even though there was no manipulation of the AVFM. It is suggested that the right dominant transverse-sigmoid sinuses are partially occluded by tentorial meningioma, developing the dural arteriovenous fistula of the right transverse sinus. An acquired origin of the dural AVFM was suggested in this case 37).
Resolution of chronic cluster headache after resection of a tentorial meningioma: case report 38).
A 28-year-old male was admitted to our hospital with the complaints of numbness of the left upper limb and gait disturbance. Neurological examination disclosed slight left dysmetria, truncal ataxia and sensory disturbance at the dermatome of C8 and Th1. CT and MRI scans showed a large mass lesion in the left posterior fossa, ventricular dilatation, cavum septi pellucidi and cavum Vergae, empty sella, cervical syringomyelia and left tonsilar herniation. The tumor which attached to cerebellar tentorium was totally removed and a histological diagnosis of meningothelial meningioma was made. Postoperative MRI scan demonstrated a disappearing of syringomyelia with the improved tonsillar herniation. Association of syringomyelia with brain tumor is relatively rare, so its pathogenesis was discussed 39).
A patient who had chronic cluster headache for more than 20 years. The headache immediately resolved upon resection of a tentorial meningioma. Prior reports of cluster headache as a manifestation of structural disease are briefly reviewed. In the patient described, the pain was referred from the right tentorium cerebelli to the right side of the face, in accordance with reported studies on the subjective localization of pain referred from posterior fossa structures. The accompanying abnormalities of autonomic function may have been mediated by central autonomic reflexes that are also involved in the pathogenesis of idiopathic cluster headache 40).
Embolization with temporary balloon occlusion of the internal carotid artery and in vivo proton spectroscopy improves radical removal of petrous-tensorial meningioma 41).
A case is presented of painful tic convulsif caused by a posterior fossa meningioma, with right trigeminal neuralgia and ipsilateral hemifacial spasm. Magnetic resonance images showed an ectatic right vertebral artery as a signal-void area in the right cerebellopontine angle. At operation the tentorial meningioma, which did not compress either the fifth or the seventh cranial nerves directly, was totally removed via a suboccipital craniectomy. The patient had complete postoperative relief from the trigeminal neuralgia and her hemifacial spasm improved markedly with decreased frequency. From a pathophysiological standpoint, the painful tic convulsif in this case was probably produced by the tumor compressing and displacing the brainstem directly, with secondary neurovascular compression of the fifth and seventh nerves (the so-called “remote effect”) 42).