Origin of carcinomas causing bladder neck obstruction demonstrated by immunoperoxidase localisation of specific antigens.

The immunohistological demonstration of prostate specific acid phosphatase, prostate specific antigen, epithelial membrane antigen and keratin was used to ascertain the origin of five advanced carcinomas involving the bladder neck and causing obstruction. Five prostatic carcinomas, 10 transitional cell and 10 squamous cell carcinomas with schistosomiasis of the bladder were studied for comparison. The concomitant localisation of prostate specific antigen and keratin was most useful in ascertaining the origin of tumour invading the bladder in contrast to the multiple use of other epithelial markers. It showed that 2/5 were of prostatic origin and 3/5 were urothelial. The markers did not discriminate with certainty between invasive poorly differentiated transitional or squamous cell carcinomas.