Refractory proctosigmoiditis caused by myointimal hyperplasia of mesenteric veins: report of a case

Proctosigmoiditis occurring in young adults is usually idiopathic and usually responds to medical management. If the process progresses to pancolitis and is refractory to medical management, proctocolectomy may be required. Myointimal hyperplasia of mesenteric veins, though rare, may also cause proctosigmoiditis, but this entity, in contrast to the idiopathic variety, does not respond to medical management; surgical excision limited to the involved colonic segment is curative. Because the treatment of the two entities differs significantly, it is important to distinguish them diagnostically. The purpose of this case report is to increase awareness of myointimal hyperplasia of mesenteric veins and to emphasize the clinical features that distinguish it from idiopathic proctosigmoiditis.

We report the case of a twenty-two-year-old male with an inflammatory process involving the distal colon and rectum, initially thought to be idiopathic proctosigmoiditis. The inflammation did not respond to an extensive course of medical management, and the patient developed complications associated with both the disease process and his medical therapy. Surgical resection of the rectosigmoid was performed.

Histologic examination of the resected colon revealed the underlying process to be colonic ischemia caused by myointimal hyperplasia of mesenteric veins not associated with idiopathic inflammatory bowel disease or systemic vasculitis.

Proctosigmoiditis caused by myointimal hyperplasia of mesenteric veins and idiopathic proctosigmoiditis may present in a similar fashion. Although patients with myointimal hyperplasia of mesenteric veins do not respond to medical management, segmental resection is usually curative, and long-term drug therapy or even proctocolectomy can be avoided. Physicians should consider the possibility of myointimal hyperplasia of mesenteric veins when patients with apparent idiopathic proctosigmoiditis do not respond to medical therapy.