Ectopic ampulla of vater in D4 with adenosquamous carcinoma: case report and literature review.

Ampulla of Vater (AOV) is typically located in the second part of the duodenum. There are few reported cases of ectopic AOV over the line extending from the pylorus of the stomach down to the distal part of the duodenum. However, to the best of our knowledge, there are only five cases reported in the English literature of an ectopic AOV in the fourth part of the duodenum, with only one of them having adenocarcinoma of the ampulla. Hereby, we report the first case of ectopic AOV in the fourth part of the duodenum, presenting with obstructive due to adenocarcinoma with focal squamous differentiation. This is the case a 42-year-old lady who had a sleeve gastrectomy for morbid obesity in the past. She presented with right upper quadrant pain for one month associated with subjective fever, unintentional weight loss, pale stool, and dark urine. The physical examination revealed a deeply jaundiced lady with an unremarkable abdominal exam. A computed tomography scan of the abdomen revealed intrahepatic and extrahepatic biliary dilation with ectopic insertion of the distal CBD into the fourth part of the duodenum with no evidence of biliary stones. She underwent pancreaticoduodenectomy after difficult biliary decompression. Histopathological diagnosis was moderately differentiated adenocarcinoma, pancreaticobiliary type with focal squamous differentiation. Ectopic AOV is a very rare entity, especially when it is associated with adenosquamous carcinoma changes.