Heterotopic Pancreatic Tissue in Gallbladder: A Report of an Unusual Entity at an Extremely Rare Location.

Background & Objective: Heterotopic pancreas (HP) or ectopic pancreas is the occurrence of pancreatic tissue in an atypical location with absence of any neurovascular or anatomic connection with the normal pancreas. In an autopsy series, the incidence of this embryologic anomaly is 0.55% to 13.7% of patients. Gallbladder is an extremely rare site for ectopic pancreatic tissue with approximately 40 documented cases. Case Presentation: We hereby report a case of incidental discovery of ectopic pancreatic tissue in the excised gallbladder from a 27-year-old female who presented with nausea, vomiting, and abdominal pain intermittently. The gallbladder lumen was filled with biliary sludge containing a single gallstone. Histopathology revealed chronic cholecystitis along with a tiny focus of ectopic pancreatic tissue comprising only pancreatic acini. Conclusion: This case highlights that histopathology should be mandatory for all excised gallbladder specimens and that this entity should be considered among the differentials for nodular/polypoidal gallbladder lesions. Although the cases where the ectopic pancreas is discovered incidentally do not have much clinical significance, this may prevent the patient from undergoing more aggressive treatment reserved for conditions like pancreatitis or malignancy in cases where the ectopic pancreas mimics a malignancy.