Papillary tumor of the spinal cord: report of 2 cases.

Abstract

Intramedullary spinal cord tumors constitute a small fraction of central nervous system tumors in the pediatric population; of these, the majority are ependymomas or astrocytomas. We report 2 pediatric spinal cord tumor cases with unique morphologic and immunohistochemical features. The first patient presented at age 7 with an intramedullary tumor of the thoracic spine. She suffered lumbar, cerebellar, and temporal lobe recurrences despite surgical resection and radiation. The second patient presented at age 17 with an intramedullary tumor of the cervical spine. The tumor recurred locally and in the cerebellum. Magnetic resonance imaging studies demonstrated gadolinium enhancement in each case. Microscopy showed papillary and solid cytoarchitecture with monomorphous epithelioid cells arranged around vascular papillae. Immunohistochemistry in each case revealed diffuse epithelial membrane antigen, cytokeratin, and E-cadherin reactivity. Glial fibrillary acidic protein staining was focal in case 1 and completely negative in case 2. Neural cell adhesion molecule showed patchy membranous reactivity and synaptophysin was negative. Electron microscopy showed ependymal differentiation. The clinical features, including propensity for recurrence and remote subarachnoid spread, and the pathologic features of these tumors are reminiscent of papillary tumor of the pineal region, ependymoma, and choroid plexus papilloma. The cases presented may constitute a new neoplastic entity within the recently described spectrum of central nervous system tumors with ependymal features.