[Two cases of mucinous adenocarcinoma of the prostate]

We report two cases of mucinous adenocarcinoma of the prostate. A 56-year-old man underwent subcapsular prostatectomy under the diagnosis of benign prostatic hyperplasia in 1968, and was found to have mucinous adenocarcinoma of the prostate, which proved to be prostatic acid phosphatase (PAP) and prostate specific antigen (PSA) positive, and carcinoembryonic antigen (CEA) negative by immunohistochemical staining. Subsequently he received 70 Gy of irradiation to the prostate, but died in 1976, when serum PAP was elevated. Autopsy revealed metastases to the liver, lungs, bone, peritoneum, spleen, pancreas, lymph nodes, and no primary gastrointestinal adenocarcinoma. The other case was a 57-year-old man, who underwent transurethral resection (TUR) for papillary tumor located just lateral to the verumontanum in 1982. The tumor was misdiagnosed as adenomatous polyp, and was PSA and PAP negative, and CEA positive. After 3 TURs of the recurrent tumor on the prostatic urethra, he underwent prostatourethrectomy, pelvic lymphadenectomy, and cystostomy for radical cure in 1985. The specimen proved to be mucinous adenocarcinoma of the prostate. He suffered recurrence of the tumor in the retrovesical space in 1987, and died in 1990. Autopsy revealed no evidence of metastasis except the local recurrence and no primary gastrointestinal adenocarcinoma.