Heterotopic pancreas as lead point in intussusception: new variant of vitellointestinal tract malformation.

Two cases of intussusception are reported with heterotopic pancreatic tissue attached to and draining into the ileum. The first patient, a boy aged 16 months, presented with ileoileal intussusception. The diagnosis was confirmed on ultrasound scan. Laparotomy and resection were performed. A 12-mm nodule of heterotopic pancreatic tissue was identified in the ileal serosa at the apex of the intussusceptum, fully formed with acinar tissue, islets, and draining duct. The second patient, also a boy aged 16 months, presented with obstructed ileocolic intussusception in which the lead point at surgery resembled a Meckel's diverticulum. Histopathology revealed a similar 10-mm nodule of fully formed pancreatic tissue in the ileal serosal tissues, with some acinar tissue extending through the wall of the intestine alongside ductal structures. In both cases there was ectopic gastric mucosa either in the distal part of the draining duct or in the small intestine itself at the opening. Heterotopic pancreas is a rare cause of intussusception. We propose that this lesion is of vitellointestinal tract origin, conceptually similar to a Meckel's diverticulum but without a diverticulum as such. Heterotopic pancreatic tissue occurring alone is more common in the proximal small intestine, duodenum, and stomach than in the ileum, and it is often asymptomatic.