ABSTRACT
The clinical and pathological features of a paraganglioma arising in the cauda equina is described and compared with previous reports. The right microscopic fetures were similar to those of paragangliomas from other sites, with a 'Zellballen' pattern of cells containing arzyrophil granules. Immunohistocytochemical stains for neurone specific enolase, S-100 protein, cytokeratin were positive, but stains for glial fibrillary acidic protein were negative. Electron microscopy showed densely staining membrane-bound granules, cilia like structures and fibros bodies in the cytoplasm. The last two features only occur in paragangliomas from this site. The pathological findings suggest that paragangliomas in this site arise from pre-existing paraganglia, possibly of the visceral autonomic group.