Papillary tumor of the pineal region
The WHO 2007 definition of Papillary tumor of the pineal region (PTPR) is as follows: – “A rare neuroepithelial tumor of the pineal region in adults, characterized by papillary architecture and epithelial cytology, immunopositivity for cytokeratin and ultra structural features suggesting ependymal differentiation.“ 1).
First described by Jouvet et al., in 2003 who reported six cases and called it “Papillary Tumor of Pineal region.” The tumor’s clinicopathological characteristics as described and illustrated in that series were very similar to the description of some entities reported by neuropathologists from different parts of the world. Many more independent case reports were published after Jouvet et al.’s initial report 2).
Various other names, like papillary pineocytoma, pineal parenchymal tumor, choroid plexus tumor, ependymoma and papillary meningioma have been given to these tumors in earlier reports 3).
They arise from specialized ependymocytes in the subcommissural organ, which is located in the pineal region. Characterized by papillary architecture and epithelial cytology, immunopositivity for cytokeratin and ependymal differentiation. It is considered grade II-III by the World Health Organization.
A review of the literature was performed to collect all the cases published with gross total resection and no complementary treatment. In conclusion, there is still much to be learned about the pathogenesis, prognosis and management of this tumor. 4).
Papillary tumor of pineal region (PTPR) arises exclusively in the pineal region and occurs most commonly in adults with slight preponderance in females.
Till 2008, about 64 cases of PTPR have been reported 5)
The clinical behavior is often aggressive. Headache of short duration is the common presenting symptom. This occurs due to increased intracranial tension as a result of compression of the aqueduct.
They may also have a cystic component. CT imaging shows their hypodense nature and enhancement with contrast. MRI demonstrates hypointensity in T1-weighted (T1W) sequence and hyperintensity in T2-weighted (T2W) sequence and enhance with contrast 6).
Limited reports suggest surgical resection is the mainstay of treatment
The findings suggest that radiotherapy provides durable local control, particularly when administered in the adjuvant setting after GTR 7).
Little is known about the prognostic markers that might aid to identify patients at increased risk for recurrence. Therefore, the prognostic value of histopathologic and clinical features was examined in a series of 21 patients. Median age of the 12 male and 9 female patients was 35 years (range, 10 to 56 y). On histopathologic examination, all tumors were characterized by loose papillary structures and tumor cells forming broad perivascular pseudorosettes showing cytokeratin expression. In addition, tumors showed increased cellularity (n=4; 19%), nuclear pleomorphism (n=4; 19%), solid growth (n=11; 52%), necrosis (n=8; 38%), increased mitotic activity (≥3 mitoses per 10 high-power fields [n=10; 48%]), and increased proliferation (Ki67/MIB1 index ≥10% [n=8/20; 40%]). Gross total resection could be achieved in 13/21 patients (62%). Postoperatively, 13 patients received radiotherapy and 4 patients chemotherapy. Median recurrence-free survival was 66 months in 19 patients, for whom detailed follow-up information was available. Twelve patients (63%) experienced tumor progression. Three patients (16%) died of disease. Among the clinical and histopathologic features examined, only increased mitotic activity (52 [8 to 96] vs. 68 [66 to 70] mo [median [95% confidence interval]]) and proliferative activity (29 [0 to 64] vs. 67 [44 to 90] mo) were significantly associated with recurrence (P<0.05). Tumors of the 3 patients who had succumbed to disease showed increased mitotic and proliferative activity.
Increased mitotic and proliferative activities are associated with worse prognosis in papillary tumors of the pineal region 8).
A 34-year-old male with headaches, blurred vision and normal examination. Radiological study showed a nodulocystic lesion in the pineal region compatible with pineocytoma. Surgery was performed using an infratentorial supracerebellar approach, finding a cystic tumor in the quadrigeminal cistern which was completely resected. Histopathology reported a papillary tumor of the pineal region. The patient made good progress without adjuvant therapy, and after 57 months of follow-up he remained asymptomatic and free of recurrence 9).