Case of the Month #161

At laparotomy, the lesser omentum protruded anteriorly, with bowel loops passing through the foramen of Winslow. Dilated cecum, ascending colon, and terminal ileum were visualized within the lesser sac after incising the gastrohepatic omentum confirming the radiographic diagnosis. After applying considerable pulsion and traction, the hernia was reduced, and the right colon returned to its proper anatomic position. The bowel was viable, with no signs of ischemia or perforation. Because recurrence was thought to be unlikely, the foramen of Winslow was not closed, and the only preventative measure taken was placement of the omentum in the right upper quadrant. There were no significant surgical or postoperative complications, and the patient was discharged 8 days after admission. The foramen of Winslow, also known as the epiploic foramen, is a normal orifice between the lesser sac and the peritoneal cavity. It is bounded by the lesser omentum and portal triad (common bile duct, hepatic artery, and portal vein) anteriorly, the inferior vena cava and covering peritoneum posteriorly, the caudate lobe of the liver superiorly, and the duodenum inferi orly [I]. Herniation of bowel through this opening into the lesser sac is one of the rarest causes of intestinal obstruction, accounting for only 8% of internal hernias and 0.08% of all hernias [3,4]. Since Blandin's initial case in 1834 [5], 170 cases have been reported of herniation through the foramen of Winslow, often associated with intestinal obstruction [6]. The 3 most common sites of involvement are the small intestine (53%- 63%), the cecum- terminal ileum (25%- 30%), and the transverse colon (7%) [4,7,8]. Other rarer sources of herniation include the gallbladder, Meckel's diverticulum, or small bowel diverticulum [9-11]. Despite the aforementioned findings, barium studies may impair the diagnostic utility of subsequent CT imaging, and, when available, CT is the modality of choice after plain radiography. As in this case, CT will allow for definitive diagnosis and will show the precise anatomical relationship of abdominal contents. Intestinal loops will be seen in the lesser sac [I]. The air and/or fluid collection in the lesser sac will extend to the foramen of Winslow located posterior to the portal triad and anterior to the inferior vena cava (PVC) [18]. As demonstrated in our images, the involved bowel will terminate as a pointed or beak-like contour as it is narrowed by the foramen [18]. Other potential f