ABSTRACT
A 64-year-old man, was admitted to the Department of Gastroenterology at another hospital in October, 2005 because of constipation and urinary retention. Endoscopic and computed tomographic (CT) examinations of biopsy specimens obtained from the rectal mucous membrane which appeared to be thickened revealed evidence of proctitis but no evidence of malignancy. The patient was referred to our hospital because of a high prostate specific anyigen (PSA) level (74.17 ng/ml), and hydronephrosis accompanied with hydroureter at the right side. Biopsy specimens taken from a prostatic tumor through a transrectal route showed histological features consistent with anaplastic adenocarcinoma which was positively stained with PSA antibody. We treated the patient with maximium androgen blackade (MAB), resulting in a decrease in plasma PSA level and amelioration of constipation as well. A 77-year-old man, visited a hospital because of constipation and high plasma carcinoembryonic antigen and carbohydrate antigen (CA) 19-9 values in May, 2005, and was diagnosed as having hyperplastic mucous membrane and atypical glands of the rectum by means of a rectal biopsy. Having been referred to our hospital, the patient received a prostate biopsy, specimens of which revealed moderately differentiated adenocarcinoma with negative PSA staining. A pelvic evisceration was performed. The eviscerated samples showed no abnormality in the rectal mucous membrane but cancer with light PSA staining in the prostatic ducts. The hormone therapy was initiated in the patient under the diagnosis of anaplastic cancer in the prostate. Since the therapy for the invasion of prostatic cancer on the rectum differs markedly from that for a primary tumor in the rectum, it is very important to differentiate accurately the one from the other.