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Background: Pineal gland tumors range from the well-differentiated “pineocytoma” [World Health Organization (WHO) grade I], which have a very good prognosis, to the aggressive and poorly differentiated “pineoblastoma” (WHO grade IV) with “pineal parenchymal tumor of intermediate differentiation” (PPTID; WHO grades II and III) occupying intermediary differentiation and prognosis. Papillary tumor of the pineal region (PTPR; WHO grades II and III) is a distinct entity with propensity for recurrence and spinal dissemination. However, the diagnostic criteria to differentiate these entities, especially between WHO grades II and III of both PPTID and PTPR, remain nebulous. Objective: To evaluate the relative frequency of the individual entities and histomorphological (including the proliferation indices) features across the spectrum of pineal parenchymal tumors (PPTs) [including PTPRs] along their course. Design: All cases of PPTs were retrieved, reviewed, and graded based on the histological criteria defined in the literature. Results: PPTID, more commonly seen in young adults, was the most common subtype of PPT. This was followed by pineoblastoma which was more commonly seen in children. Clinical progression was seen in both grades II and III of PPTID; however, it was more commonly seen in cases with a MIB1 labeling index of >10%. PTPRs (both grades II and III) showed an aggressive histological transformation and also intraparenchymal metastasis. Conclusion: PPTIDs are the most common adult primary PPTs and have the potential to progress and disseminate in both grades II and III. Both grades of PTPRs have a metastatic potential. These findings suggest the need for postoperative adjuvant therapy in both grades of PPTID and PTPR.

Papillary tumors of the pineal region (PTPR) are very rare. We describe the first report of a PTPR empirically managed with gamma knife radiosurgery. The patient was initially shunted and referred for empirical gamma knife radiosurgery. After initially showing some improvement, he had recurrence of tumor after 7 years. For recurrence he underwent a gross total resection and the biopsy established the diagnosis of PTPR. Further research needs to be done as to the efficacy of gamma knife surgery for PTPR. In addition, the role of stereotactic biopsy for eligible patients should be considered as the initial step to direct the treatment of choice.

Papillary tumors of the pineal region (PTPRs) are rare and are recognized as a distinct entity in the recent 2007 World Health Organization (WHO) classification of tumors of nervous system. Till date, only 55 cases have been reported. We report another three patients of PTPRs with characteristic radiological features. Histologically, all the three patients exhibited remarkable uniform histology of epithelioid morphology with variable presence of single to multilayered papillary architecture. Consistent absence of fibrillary matrix was noted in all the three cases. None of the cases showed aggressive histology. A large multicenter study is essential for upfront characterizing the biological behavior, as frequency of these tumors is very low.

Papillary tumors of the pineal region are recently described as rare mass lesions with limited literature available on their natural history and imaging features. Magnetic resonance imaging (MRI) including perfusion, diffusion, and spectroscopic features were described in an 18-year-old girl with papillary tumor of pineal region. A well-defined, T1 hyperintense and contrast-enhancing mass lesion was noted in pineal region with few cystic spaces within. Solid portion of lesion showed minimal diffusion restriction with average apparent diffusion coefficient of 0.812 Χ 10 -3 mm 2 /s; on MR spectroscopy elevated myo-inositol peak with reduced N-acetylaspartate and elevated choline in the tumor. On perfusion study there was significantly high relative cerebral blood volume (rCBV) (6-9 times) and relative cerebral blood flow (rCBF). Our findings agree with previous descriptions of cystic areas with T1 hyperintense appearance of this tumor but very high level of tumor perfusion, diffusion restriction, and presence of myo-inositol peak are important imaging findings and may correlate with the recent reports of high tumor recurrence in these cases.