Abstract
A 74-year-old man was admitted with a defecation disorder. His serum PSA level was extremely elevated. A barium enema showed a circular stenosis of the lower rectum. On colonoscopy, a circular stenosis with red, edematous and irregular mucosa was observed. EUS and MRI revealed an indistinct boundary between a hypertrophic prostate and the rectum. A needle biopsy of the prostate was performed. Histological analysis of the specimens showed poorly differentiated adenocarcinoma with positive staining for PSA. We diagnosed prostate cancer with rectal invasion and conducted hormonal therapy. Two months later, the serum PAS level dropped to the normal range. On colonoscopy, the circular rectal stenosis had improved but a small depressed rectal cancer was observed on the same site.