285 Why Routine Histopathology Matters: A Case of Unsuspected Pancreatic Heterotopia in the Gallbladder

Abstract Introduction Heterotopic pancreas, or ectopic pancreas, is a rare developmental anomaly defined as pancreatic tissue located outside its normal anatomical position and without ductal or vascular continuity with the orthotopic pancreas. While commonly found in the stomach, duodenum, or jejunum, its occurrence within the gallbladder is exceedingly rare and typically discovered incidentally during histopathological examination following cholecystectomy. Case Presentation We report the case of a 36-year-old female who presented with intermittent upper abdominal pain and dyspepsia. Serial imaging identified gallbladder polyps and, eventually, a solitary gallstone. Due to persistent symptoms, an elective laparoscopic cholecystectomy was performed. Intraoperatively, the gallbladder appeared macroscopically unremarkable. Histopathological evaluation revealed ectopic pancreatic tissue measuring 0.4 mm within the gallbladder wall, characterized by eosinophilic acinar structures located between the lamina propria and muscularis propria, consistent with Type II heterotopic pancreas. No dysplasia or malignancy, but associated chronic inflammation was noted. Discussion Heterotopic pancreatic tissue in the gallbladder is extremely uncommon, with only a limited number of cases reported in the literature. Its asymptomatic presentation and non-specific imaging findings often mimic common biliary pathology, rendering preoperative diagnosis difficult. While generally benign, heterotopic pancreas may cause inflammation or contribute to symptoms and, in rare cases, undergo malignant transformation. Surgical excision remains both diagnostic and therapeutic. Conclusions This case emphasizes the importance of routine histopathological assessment of cholecystectomy specimens, especially in patients with atypical symptoms or inconclusive imaging. Recognition and reporting of heterotopic pancreas in rare locations such as the gallbladder are essential to improve clinical awareness, avoid misdiagnosis, and guide appropriate management.