A 63-year-old man was admitted to the hospital with chronic partial intestinal obstruction and at the time of operation was found to have an internal omphalocele. All of the midgut was trapped in the peritoneum; an incidental carcinoid of the duodenum was present. Partial release of the small intestine (performed by peeling off the sac) and gastrojejunostomy cured the patient. In an internal omphalocele, the whole midgut, with its sac (the fusion of the external peritoneum and the body peritoneum), is reduced into the peritoneal cavity. It is thus to be differentiated from paraduodenal hernia, where the contents of the sac include only the prearterial segment of the midgut and where the hernia is retrocolic.
Satyanand , Gulati SM, Thusoo TK. Internal OmphaloceleA Distinct and Separate Entity From Paraduodenal Hernia. Arch Surg. 1974;108(2):233–234. doi:10.1001/archsurg.1974.01350260087021