Prostatic carcinoma presenting as acute obstruction of large bowel

Carcinoma of the prostate classically presents with symptoms of obstructive uropathy or cachexia due to generalized metastasis. Two patients who presented with acute large bowel obstruction are discussed. In both, urologic symptoms were minimal; bone surveys were negative for metastasis and acid phosphatase values were normal. One patient was decompressed by sigmoidoscopy and rectal tube and in the second a transverse bar colostomy was necessary. Prostatic carcinoma may simulate the annular constricting lesion thought solely characteristic of carcinoma of the rectum. The differentiation is important because of the wide variance in prognosis and treatment. The treatment of rectal carcinoma is primarily surgical whereas a prostatic carcinoma at this stage responds well to hormonal therapy and has a more favorable prognosis than the rectal primary. Before radical resection of the rectum is undertaken in a male, the possibility of direct extension from a primary prostatic lesion must be excluded.