A Novel Case of Primary Conus Medullaris Epithelioid Glioblastoma with Gliosarcomatous Differentiation

Intramedullary location is seldom seen in spinal cord neoplasms. Ependymomas and astrocytomas comprise the vast majority of these intramedullary lesions. Primary spinal origin is rarely seen in gliosarcomas. No epithelioid glioblastomas have been reported in the spine. We describe the case of an 18-year-old male who presented with symptoms suggestive of a spinal mass lesion. Magnetic resonance imaging revealed a homogeneous intradural-intramedullary lesion involving the conus medullaris. Biopsy of the lesion showed a unique morphology comprising gliosarcoma and epithelioid glioblastoma differentiation, supported by relevant immunohistochemistry. The prognosis of such an entity is expected to be poor. However, the presence of mutant BRAF V600E, as seen in the current case, and the availability of targeted therapy against it are expected to improve the prognosis.