Paraganglioma of the urinary bladder.

A paraganglioma of the urinary bladder in a 60-year-old woman presented with irritative voiding symptoms, without hematuria or hypertension. Sonography revealed a well-limited ovoid mass of the posterior wall, and cystoscopy showed that it was covered by normally appearing mucosa. Treatment consisted of transurethral resection, and the patient has been followed for 2 years without recurrence. Histologically the lesion consisted of small nests of spindle cells with clear to acidophilic cytoplasm; mitotic activity was inconspicuous. Immunohistochemical analyses revealed that the tumor cells were strongly positive for neuron-specific enolase and chromogranin A, and negative for cytokeratin, vimentin, neurofilaments, glial fibrillary acid protein and HMB 45. Sustentacular cells at the periphery of neoplastic cell clusters were positive for S-100 protein.