A 47-year-old woman presented with signs and symptoms of acute cholecystitis. A routine cholecystectomy was performed. No gallstones were present. On histological examination of the gallbladder, a nodule impinging on the lumen was present in the region of the cystic duct. This nodule was composed of mature, uninflamed exocrine and endocrine pancreatic tissue. In the absence of gallstones, the heterotopic pancreas was the cause of obstruction, with subsequent cholecystitis.