Meckel diverticulum is an anomaly seen in about 2% of the population with a slight male predominance. It is persistent proximal portion of the vitelline duct. Other congenital anomalies may coexist. Location is approximately 80 cm proximal to the ileo-cecal valve on the outer mesenteric border. It is usually lined by small intestinal mucosa but may also contain gastric, duodenal, colonic or pancreatic tissue. Image courtesy of: Tracy Halvorson, MD; Dept. of Pathology, University of Iowa Hospitals & Clinics, Iowa City, IA.