Adenocarcinoma arising from the prostatic duct mimicking transitional cell carcinoma.

A 71-year-old man was first diagnosed with primary transitional cell carcinoma of the prostate with a skip lesion on the distal urethra. The patient received three courses of intra-arterial chemotherapy of cisplatin (CDDP) and pirarubicin (THP-ADM) followed by a radical prostatectomy. Histopathologic examination of the prostatectomy specimen revealed adenocarcinoma invasion along the prostatic duct extending to the peripheral acini, which was diagnosed as ductal adenocarcinoma. The clinical and histopathologic features of this case are entirely different from usual adenocarcinomas of the prostate. This rare histopathologic feature should be recognized as 'ductal carcinoma of the prostate', to distinguish it from papillary adenocarcinoma or adenocarcinoma with endometrioid features. The patient has had no sign of recurrence 14 months after the operation. CDDP-based chemotherapy followed by radical prostatectomy may be one of the promising therapeutic modalities for this rare entity.