Multiple minute nests of incidentally detected paraganglionic cells associated with urothelial carcinoma of the urinary bladder in a 73-year-old woman

A 73-year-old woman who had undergone resection of urothelial carcinoma (UC) (G3 > G2) of the ureter was also found to have UC (G3) in the urinary bladder, spread throughout the urinary bladder with multiple foci of carcinoma in situ and small papillary cancers. Total cystectomy was therefore performed. On detailed microscopic examination of the extirpated urinary bladder, multiple minute cell nests, 14 in number and less than 2 mm in diameter each, consisting of cells harboring small nuclei and clear cytoplasm, were incidentally detected within the sub-mucosal layer and the proper muscle layer, mainly in the posterior wall of the urinary bladder. Some cell nests were clearly associated with ganglion cells. The cells in minute nests were positive on Grimelius staining and also strongly positive on staining with antibodies to chromogranin A, neuron-specific enolase (NSE), synaptophysin, and vimentin on immunohistochemical staining. In addition, sustentacular cells in the minute cell nests were positive for S100 protein. Staining with antibodies to pancytokeratin AE1/AE3, glial fibrillary acidic protein, and p53 was negative in the cell nests. Based on these findings, the multiple minute foci were diagnosed as paraganglionic cells (PGCs) incidentally detected in the urinary bladder of an elderly woman, in association with UC. Although PGCs are rarely detected in adult human urinary bladder on routine histopathological examination, the possibility of their existence should be kept in mind by pathologists, especially in coexistence with UC. This is the first case of PGCs associated with UC in the human urinary bladder in the English literature.