[Pancreatic choristoma in the gallbladder: report of two cases].

Pancreatic choristoma is the occurrence of normal pancreatic tissue in an abnormal location without any anatomic continuity with the main body of the gland. Although heterotopia is uncommon in the gallbladder and biliary tract, anecdotic cases of gastric mucosa, liver, adrenal gland and pancreas among other tissues have been described. We report an eight year-old male and a 22 year-old female, electively operated for symptomatic cholelithiasis. On pathology, a nodule identified as a pancreatic endocrine and exocrine choristoma, was found in the gallbladder wall of both patients. We employed immunohistochemistry to characterize this choristoma. Tubular and epithelial structures were immunoreactive to cytokeratins 7, 8, 18, 19 and 20 and to CA19-9. Exocrine activity was documented by immunoreactivity to al-antitrypsin and al-chemotrypsin. Other immunohistochemical markers such as insulin and somatostatin were positive identifying endocrine activity.