Giant Cell-rich Tanycytic Ependymoma as Intramedullary Spinal Mass

Intramedullary spinal cord tumors are rare neoplasms and harbour full spectrum of primary neoplasms as seen within the intracranial compartment. They include tumors with diverse pathologies, arising in both adults and children and pose considerable diagnostic challenge. The differentials at this site include wide ranging pathologies from benign, circumscribed pilocytic to diffuse astrocytoma, myxopapillary or tanycytic ependymoma and malignant diffuse midline glioma. Rare instances of glioneuronal tumors, pleomorphic xanthoastrocytoma have also been described at this location. H3K27M mutant diffuse midline high grade glioma is the new entry to this list in 2016 updated WHO classification. We describe the morphologic features of a diagnostically challenging intramedullary spinal cord tumor masquerading as a high grade lesion due its cellular composition and discuss its differentials. The report also emphasizes the role of already established and recently introduced immunohistochemical markers and other ancillary techniques as useful adjuncts in the diagnosis.