Context Heterotopic pancreas is a rare entity. Thirty-three cases in the gallbladder have been reported. We describe the first case of heterotopic pancreas mimicking a gallbladder cancer, identified within a calcified lesion in the thickened posterior wall of the gallbladder. Case report A 72-year-old woman with right upper quadrant pain was referred with a suspicion of gallbladder neoplasia. A CT scan demonstrated a 1 cm thickened posterior wall of the gallbladder with a 2 mm punctate calcification. An open cholecystectomy was carried out without complication. The frozen section demonstrated pancreatic tissue. Conclusion Heterotopic pancreas of the gallbladder is highly uncommon. It can mimic a neoplastic process in the gallbladder, particularly in the context of calcification. Its malignant potential in the gallbladder is unknown, in contrast to previously described neoplastic transformation with gastric heterotopic pancreas.