[A Case of Mucinous Adenocarcinoma Extending to Bladder Neck and Prostate].

A 56-year-old man visited a clinic with the chief complaint of frequent micturition and residual sensation of urine. He was referred to our hospital for close examination. Cystoscopy showed a tumor protruding toward the bladder neck from the prostate with stones and debris on the surface. Magnetic resonance imaging showed an encapsulated tumor of iso-intensity in the prostate in T2-weighed images. Prostate specific antigen was 0.88 mg/dl. Transurethral resection of prostate was performed under the diagnosis of benign prostate hyperplasia. During the operation, a solid tumor with mucus deposit was observed. Intraoperative rapid pathological diagnosis was mucinous adenocarcinoma. A radical cystectomy was performed. Pathologically, mucinous adenocarcinoma was distributed in the bladder neck, the prostate and surrounding tissue, but the prostatic urethra was intact. The surgery was assessed to be curative. Neither neoadjuvant nor adjuvant chemotherapy was performed, since the effectiveness of chemotherapy for mucinous adenocarcinoma arising from urothelial epithelium has not been established.