Brain, Papillary tumour of the pineal region

Papillary tumour of the pineal region (PTPR) is a rare neuroepithelial neoplasm thought to arise from the subcommissural organ located in the posterior wall of the third ventricle at the entrance of the cerebral aqueduct. It typically occurs in adults and due to its location, it presents with CSF obstruction and hydrocephalus. Microscopically, PTPR has a papillary and/or solid architecture with epithelioid cells that may contain cytoplasmic vacuoles. Ependymal features (perivascular pseudorosettes, true rosettes) can be seen. Immunohistochemistry shows positivity for cytokeratins, S100, and focal and variable staining for GFAP. Prognosis is generally guarded and the biologic behaviour corresponds to WHO grade II or III but histologic grading criteria remain to be defined.