Prostatic carcinosarcoma: a case originating in a previous ductal adenocarcinoma of the prostate.

Ductal adenocarcinoma of the prostate is a variant of prostatic carcinoma that appears to originate in the ducts of the prostate. Carcinosarcoma of the prostate is an uncommon and aggressive tumour composed of an intimate admixture of adenocarcinoma and sarcoma. In this report we describe the clinicopathological and immunohistochemical characteristics of a case of prostatic carcinosarcoma that appeared in a 66-year-old man who had had a ductal adenocarcinoma of the prostate diagnosed 3 years previously. The patient died of the disease 3 months after the carcinosarcoma was diagnosed. This case may represent further evidence of the dedifferentiation theory in the origin of carcinosarcoma. The case also illustrates that this dedifferentiation may occur from any type of prostatic carcinoma.