Intestinal obstruction after colostomy closure.

(See pages 1030–1 for the Photo Quiz) Figure 1. The dimensions and the unilateral, flattened shape of the longitudinally sectioned structures clearly identify these as eggs of Enterobius vermicularis (thin arrows). The thick arrow indicates an elongated structure protruding from 1 of the eggs; this represents a hatching larva trapped in the inflammatory mass (original magnification, ϫ40). Diagnosis: inflammatory mass surrounding eggs of Entero-bius vermicularis. The hematoxylin-eosin–stained sections (figures 1 and 2) show multiple eggs of E. vermicularis at the site of anastomosis. The eggs are embedded in necrotic tissue, surrounded by an area of fibrosis with a histiocytic infiltrate and frequent eosin-ophils. E. vermicularis are roundworm parasites that live on the mucosa in the distal parts of the colon. Females migrate to the perianal area to deposit their eggs on the skin. This results in pruritis, with subsequent transmission via the fecal-oral route. In patients with a colostomy, the eggs may be deposited on the protruding colonic mucosa. In this patient, the restoration of the bowel continuity involved the mobilization of the colon from the abdominal wall. Subsequently, the proximal and distal parts of the colon were joined together with a stapler. During the stapling procedure, eggs (some of which were in the process of hatching) must have been trapped in the sutures, resulting in a foreign body reaction and the formation of a large ob-Figure 2. At higher magnification, the cellular structure of the intact Enterobius vermicularis larva can be recognized (original magnification, ϫ100). structing inflammatory mass. The patient was treated with me-bendazole, and treatment was repeated after 14 days. Unfortunately , the second anastomosis was complicated by leakage. At present, the patient has a permanent end colostomy because of the persistent rectal fistulae.