RARE-52. AN EXTRA-VENTRICULAR NEUROCYTOMA PRESENTING WITH DIFFUSE LEPTOMENINGEAL DISEASE WITH OPTIC NEURITIS, A CASE REPORT

Abstract INTRODUCTION Neurocytoma is classically a rare intraventricular tumor that affects young adults. Due to its location, it usually presents with obstructive hydrocephalus and typically has a favorable prognosis after adequate surgical intervention. CASE: In this report, we describe the case of a 19-year-old man who developed progressive decreased visual acuity and headaches that led to a diagnosed of hydrocephalus and a ventriculoperitoneal shunt (VPS) placement. Work up at presentation revealed a thoracic spinal cord tumor which was completed resected and pathology was consistent with extra-ventricular neurocytoma. With no further intervention, he experienced signs of worsening intracranial pressure (ICP) and visual acuity, becoming steroid-dependent. Repeat imaging 3 months later showed early signs of leptomeningeal disease (LMD), optic nerve enhancement, and diffuse dural thickening. A dural biopsy was done and read as nonspecific inflammation. He then came to our center for a second opinion. We reviewed pathology from original tumor and confirmed extra-ventricular neurocytoma. We, however, read the dural biopsy as an organizing subdural hematoma. We analyzed his cerebrospinal fluid (CSF) and cytology showed neurocytoma cells, linking his LMD to initial diagnosis. He went on to receive photon craniospinal radiation (CSI) with clinical improvement and decreased steroid requirements. Most recent imaging showed improving LMD. DISCUSSION Extra-ventricular neurocytoma is an extremely rare disease with very few cases reported in the literature and our case is unique due to the severe leptomeningeal involvement affecting the optic nerves and the presence of neurocytoma cells on the CSF. There is no consensus on how to best treat these cases, however, our patient improved after CSI.