Gastric and Pancreatic Ectopic Mucosa in the Gallbladder: A Unique Mimicker of Polypoid Lesions.

A 46-year-old woman with upper quadrant pain and nausea, diagnosed with cholelithiasis, underwent cholecystectomy. A 0.7 cm polypoid lesion in the gallbladder showed mostly heterotopic gastric mucosa with antral and oxyntic glands and foveolar epithelium. A focal area of the heterotopic pancreas, comprising acini and ducts with positive trypsin staining but no islet cells, was found. Additional findings included minimal inflammation, an adenomyoma on the opposite wall, and black gallstones, leading to a diagnosis of a heterotopic polyp. This case underscores the importance of thorough histopathological examination in diagnosing rare heterotopic tissues in the gallbladder, preventing misdiagnosis with malignant entities.