Massive rectal bleeding of colonic origin: localization of the bleeding site.

Fourteen patients with massive colonic bleeding underwent preoperative evaluation including visceral angiography and/or colonoscopy. Segmental for subtotal colectomy was performed in each case. The freshly excised colonic specimen was opened and washed clean, and the mucosal surface was closely examined by manually compressing the specimen segment by segment in order to detect the minute bleeding site(s), which were then marked with a suture for histologic sectioning. This maneuver was successful in 13 instances. In 11 of these, histologic identification was made; seven were cases of vascular malformations, and four were cases of diverticular bleeding. In 5 of these 11 cases, colonoscopy and/or visceral angiography failed to localize the bleeding sites; four were cases of bleeding of diverticular origin. Of the two patients in whom histologic identification was not made despite suture identification, one underwent a second colonic resection in which bleeding sites were histologically identified; the bleeding was not caused by vascular malformations or diverticula. The method of examining the freshly excised specimen described is useful for accurate histologic identification of the cause of colonic bleeding, particularly for diverticular bleeding. The method is also useful for immediate assessment of adequacy and appropriateness of surgical resection.