Heterotopic Pancreas as Lead Point in Intussusception: New Variant of Vitellointestinal Tract Malformation

Abstract

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.

Intussusception Secondary to Isolated Heterotopic Pancreas of the Ileum: Case Report and Review of the Literature

“…7 In rare isolated instances, heterotopic pancreas of the ileum acts as a leading point for intussusception. 5,[7][8][9][10][11][12][13] Heterotopic pancreas is defined as pancreatic tissue that has neither anatomic nor vascular continuity with the normally located pancreas. It is not uncommon, and is found in l%-2% of autopsies, and as an incidental finding in about 1 of every 500 upper abdominal operations.…”

“…Isolated heterotopic pancreas of the ileum on the other hand is very rare, usually asymptomatic and discovered incidentally during surgery for other conditions, and very rarely as a leading point for intussusception. 5,8,[10][11][12] In the series of 292 consecutive children with intussusception by Puri and Guiney, none of the 27 patients identified with leading points had isolated heterotopic pancreas. 7 In the review of 630 episodes of intussusception by Ong and Beasley, none of the 60 patients with pathological leading had isolated heterotopic pancreas.…”

“…18 In an extensive review of the literature, we found only nine cases (Table 1) of isolated heterotopic pancreas of the ileum as a leading point for intussusception in children. 5,8,[10][11][12]18 Their ages ranged from 2 months to 11 years, and in all except two, the intussusception was ileo-ileal, two of which were recurrent intussusception. Whereas idiopathic intussusception is usually seen in infants between 3 and 12 months of age, intussusceptions secondary to a pathological lesion on the other hand have a different age distribution.…”

Combined ileal heterotopic pancreatic and gastric tissues causing ileocolic intussusception in an infant

“…Isolated heterotopic pancreatic tissue in the ileum causing intussusception is extremely rare [2]. Combination of ileal serosal heterotopic pancreatic tissue and an ectopic gastric mucosa as a cause of intussusception is even more of a rarity [1]. We report a case of combined ileal serosal heterotopic pancreatic and mucosal gastric tissues causing an ileocolic intussusception in an infant.…”

“…Most intussusceptions that occur in infancy are idiopathic in origin [1]. In a small proportion of cases a pathological lead point is identified as the cause of an intussusception, with Meckel's diverticulum being the most common lesion [2][3][4].…”