Post-surgical necrobiotic granulomas of urinary bladder.

Palisading necrobiotic granulomas of the prostate are an uncommon but well-recognized sequela of transurethral surgery. Similar granulomas occurring in 3 patients after transurethral surgery of the urinary bladder are reported. In each case, the lesions were discovered as a result of biopsies done subsequent to transurethral resections of bladder tumors. An idiosyncratic hypersensitivity reaction to a diathermically induced change in the antigenicity of the subepithelial connective tissue is suggested as the cause of these granulomas.