Heterotopic pancreatic tissue obstructing the gallbladder neck: a case report

Heterotopic pancreatic tissue is defined as pancreatic tissue outside the boundaries of the pancreas that has neither anatomic nor vascular continuity with the pancreas. Heterotopic pancreatic tissue in the gallbladder is uncommon and has rarely been reported to cause symptoms. We report a case of heterotopic pancreatic tissue obstructing the gallbladder neck resulting in cholecystitis. A 26-year-old female presented with right upper quadrant abdominal pain and fever. On physical examination the right upper quadrant was tender to palpation with a positive Murphy's sign. Laboratory tests were significant for elevated aspartate aminotransferase and alanine aminotransferase. Transabdominal sonography showed gallbladder wall thickening, a positive sonographic Murphy's sign, and an apparent large non-mobile stone at the gallbladder neck. Pathologic examination revealed cholecystitis but instead of a large stone there was a tan-yellow necrotic mass at the gallbladder neck. Microscopically, the mass consisted of heterotopic pancreatic tissue containing exocrine pancreatic acini, ducts, and islets of Langerhans. The final diagnosis was acute cholecystitis secondary to obstruction by heterotopic pancreatic tissue. Although heterotopic pancreatic tissue is usually an incidental finding on pathologic exam, one should not exclude it in the differential diagnosis of symptomatic gallbladder disease of indefinite etiology.