Inverted Meckel's diverticulum.

A HEALTHY 35-YEAR-OLD PATIENT was admitted with a sudden onset of bloody diarrhea. The patient had no past record of any significant illness. Colonoscopy and upper gastrointestinal endoscopic examination did not reveal the cause of bleeding. During admission, the patient passed a large amount of grossly bloody and tarry stool. There was progressive anemia (hemogloblin level: 7.3 g/dL, hematocrit level: 21.3%). An upper gastrointestinal radiological contrast study with small intestine follow-up demonstrated a long intraluminal mass lesion about 80 cm from the ileo-cecal valve (Fig 1). The lesion appeared as a long, pedunculated polyp with shallow ulcers on its leading end. The stalk was about 10 cm in length with Kerckring’s folds. An ultrasound examination revealed an “eggplant” shaped mass lesion within the bowel (Fig 2). At laparotomy, there was a palpable mass in the distal ileal lumen, and an ileo-ileal intussusception was identified. There was a dimple in the antimesenteric ileal wall at the base of the intraluminal mass. Approximately 10 cm of the ileum containing the mass lesion was resected, and an end-to-end anastomosis was constructed. An examination of the opened specimen revealed a large polypoid lesion, with a long stalk and ulcerated mucosa (Fig 3, Top). After formalin fixation, pathological examination showed the mass lesion was formed by adipose tissue wrapped in an inverted intestinal wall, which was consistent with a Meckel’s diverticulum. The surface of the stalk consisted of ileal mucosa surrounding an