Pure prostatic papillary adenocarcinoma with ductal features.

Papillary adenocarcinoma resembling ductal carcinoma and arising in the peripheral zone is extremely rare. We report a case of prostatic papillary adenocarcinoma with ductal features. The patient was a 68-year-old man who initially presented with dysuria and sensation of residual urine after voiding. Prostatic needle biopsy findings supported pathological diagnosis of prostatitis. The symptoms were improved by medication for prostatitis, and prostate-specific antigen (PSA) level of 22.6 ng/ml descreased to 9.9 ng/ml. It remained between 7.2 ng/ml and 9.9 ng/ml for 2 years. However, it gradually increased to 11.9 ng/ml. Transrectal digital examination, T2-weighted magnetic resonance imaging (MRI) of the prostate and transrecral ultrasound showed a mass in the enlarged right side of the prostate. Transrectal needle biopsy of the mass was performed, and papillary adenocarcinoma was suspected by histological examination. Radical prostatectomy was performed. Histological and immunohistochemical examination of the prostatectomy specimen revealed pure prostatic papillary adenocarcinoma with ductal features.