Paraganglioma of the cauda equina. A case report and review of the literature.

A case of paraganglioma of the cauda equina is reported. The patient was a 55-year-old Japanese woman who complained of lower back pain and gradual weakening of the left lower extremity, she was diagnosed as having a spinal cord tumor, and the tumor was removed surgically. Histologically, the tumor was encapsulated, and consisted of solid nests of large, polyhedral epithelioid cells with abundant eosinophilic cytoplasm. The nests were separated from each other by a thin fibrovascular stroma. Grimelius staining revealed neurosecretory granules in the cytoplasm of the tumor cells. This was further confirmed by electron microscopic observation. The tumor cells were immunohistochemically positive for neuron-specific enolase (NSE), but negative for glial fibrillary acidic protein (GFAP). On the basis of the histologic, immunohistochemical and electron microscopic features of the tumor cells, the tumor was diagnosed as paraganglioma. The cauda equina is a rare location for this type of tumor, and only a limited number of cases have been reported.