GIANT CELL EPENDYMOMA OF THE THORACIC SPINE

Abstract

INTRODUCTION AND IMPORTANCE: Spinal ependymomas are slow-growing lesions that comprise the majority of primary spinal cord neoplasms. When surgery is indicated, the extent of tumor removal is most prognostic for long-term survival. Unusual histological subtypes can make intraoperative diagnosis spurious, possibly altering the surgical approach from gross total resection for ependymomas to debulking for high-grade astrocytomas. We describe a 67-year-old woman with a thoracic spine intramedullary giant cell ependymoma. She presented with decreased lower extremity sensation leading to unsteadiness and an eventual fall. A physical examination revealed lower extremity hyperreflexia and ankle clonus, but no clear sensory level. Magnetic resonance imaging demonstrated an intramedullary T1 and T2 hypointense, homogenously enhancing lesion at T8 with extensive cephalad and caudal edema. A laminectomy at T8 to T9 afforded gross total resection of the lesion that had a clear cleavage plane with normal spinal cord. Intraoperative pathology suggested a high-grade glioblastoma, but final section showed sporadic giant cells with marked pleomorphism, uniform immunofluorescence staining with both glial fibrillary acidic protein and cluster of differentiation 99, and high MIB-1 index. Electron microscopy showed "zipper-like" junctions. There were no detected genomic abnormalities consistent with glioblastoma. We present this first reported case of thoracic spine giant cell ependymoma alongside scant literature yielding 1 case in the cervical spine and 2 cases at the filum terminale. Those cases had benign courses, whereas ours demonstrates a high degree of proliferation, making the malignant potential difficult to assess.