Mucinous adenocarcinoma of the prostate with elevated serum CA19-9: A case report

Mucinous adenocarcinoma of the prostate is one of the least common types of prostatic carcinoma. We recently experienced this type of prostatic cancer. A 61-year old man was admitted to our hospital because of pollakisuria and deterioration of chronic renal failre. Imaging study revealed a large tumor involving the prostate, bladder base, seminal vesicle and adjacent tissues. Tumor markers including PSA and PAP were negative except for CA19-9 (72.40U/ml). Transrectal biopsy revealed the tumor to be a mucinous adenocarcinoma. Although extensive investigation ruled out metastatic involvement from any other organ, the origin of the tumor, either from the prostate or the bladder, remained unclear. Pelvic exenteration was performed. Immunohistochemical study proved PAP, PSA, CEA and CA19-9 in the tumor cells, lectin stain by soybean agglutinin (SBA) was positive in the tumor and a diagnosis of mucinous adenocarcinoma of the prostate, pT₄pN₂Mo, was made. Twenty nine cases previously reported in the Japanese literature, in addition to the present case, are reviewed.