Mast Cell-Rich Pleomorphic Pineocytoma: A Rare Entity

Abstract

Pineal region tumors constitute a rare group of neoplasms. Primaryneuronaltumor that intrinsicallyarisefromthepineal gland are referred to as pineal parenchymal tumors (PPTs). Their neuropathological spectrum is divided into well-differentiated “ pineocytoma ” (World Health Organization [WHO] grade I), pineal parenchymal tumors of intermediate differentiation and papillary tumor of pineal region (WHO grades II and III), and poorly differentiated “ pinealoblastoma ” (WHO grade IV). 1 Pleomorphic cytological variant of pineocytoma has been rarely reported in the medical literature mainly in form of case reports. A 45-year-old man with a recent history of right-sided stroke presented to the neurosurgery department with complaint of headache for last 1 month. Multislice computed tomography (CT) imaging revealed an ill-de fi ned hyperdense space-occupying lesion with internal calci fi cation. The tumor was located in the region of pineal gland with extension into the adjacent lateral ventricle and resultant mild obstructive hydrocephalus. MRI scan revealed a hyperdense nodular lesion measuring 24 (cid:1) 18mm with scant peritumoral edema ( ► Fig. 1A and 1B ). Following placement of a ventriculo peritoneal shunt, stereotactic biopsy was performed and submitted to the pathology department. Histopathological examination revealed a pineal parenchymal neoplasm with varied morphology. In some areas, the tumor cells were small and uniform resembling pinealocytes, and