Recurrent Papillary Tumor of Pineal Region Misdiagnosed as Pineocytoma 9-Years Ago.

Primary tumors of the pineal gland occur infrequently with a preponderance of either parenchymal tumors or germ cells tumors. Papillary tumor of the pineal region is a rare neuroepithelial lesion that arises exclusively in the pineal region. They have been designated as either Grade II or Grade III lesions as per the 2016 WHO classification of central nervous system tumors. Clinically, they usually present with obstructive hydrocephalus and visual disturbance. On imaging, these tumors are solid-cystic, heterogeneously enhancing, and show T2 hyperintensity. Pathologically, they can closely resemble a Grade I pineocytoma and immunohistochemistry is essential to differentiate the two. No definite guidelines exist to confirm the ideal protocol of treatment. Evidence regarding the role of radiation after surgery is limited to case reports and series. Adjuvant therapy is usually recommended for tumors with subtotal excision, high proliferative/mitotic index, or proven metastasis. We describe a case of a 29-year-old male with a recurrent papillary tumor of the pineal region, 9 years after primary surgery where it was misdiagnosed as a pineocytoma. The tumor was effectively controlled with surgical excision, cerebrospinal fluid diversion, and adjuvant radiation for 8 years before showing two recurrences within a span of 6 months with a rising proliferation index.