Primary Spinal Oncocytic Paraganglioma

ABSTRACT

Paraganglioma is a generic term applied to tumors of paraganglia, regardless of location, and composed largely of paraganglionic chief cells. It is a rare tumor, especially in the spinal region. When it appears in the craniospinal axis, it is restricted to the cauda equina or filum terminale, and less commonly, the spinal nerve root. We report a case of oncocytic paraganglioma in the spinal nerve root of 13-year-old girl. The tumor was located in intradural and extramedullary areas from the 12th thoracic to the 1st lumbar vertebra. Histologically, the tumor cells with abundant eosinophilic cytoplasms show diffuse compact clusters, which are surrounded by fibers in a reticulin stain, like a nested pattern. The nuclei are round to ovoid in shape with mild atypia. Immunohistochemically, the tumor cells are positive for synaptophysin, neuron-specific enolase and vimentin but are negative for cytokeratin, chromogranin and glial fibrillary acidic protein. Some cells are positive for S-100 protein. The MIB-1 labeling index is low. Ultrastructurally, dense core neurosecretory granules are not found but mitochondrias are commonly noted.