Separate annular strictures of the rectosigmoid colon secondary to unsuspected prostate cancer.

Rectal involvement from prostate cancer occurs in 1.5-11% of cases. A rarer presentation is that of a separate metastasis to the high rectosigmoid colon causing an annular stricture. We present our experience with six such cases who presented with gastrointestinal symptoms. Two of the cases had undergone intestinal resections. All 6 patients had radiographic evidence of an annular stricture in the rectosigmoid area. Retrospective review revealed evidence of metastatic disease in all cases in the form of abnormalities in one or more of the following: intravenous urography, radionuclide bone scan, liver spleen scan, acid phosphatase, or alkaline phosphatase. The mean survival was 9.3 months. This rare presentation of prostate cancer may be difficult to distinguish from primary colorectal cancer and therefore needs to be ruled out to avoid intestinal resections.