[Well-differentiated adenocarcinoma of the papilla of vater--report of a case].

Reported is the case of a 64-year-old female who was admitted to our clinic because of hyperamylasemia. Duodenal endoscopic examination revealed a tumor at the papilla of Vater. A biopsy specimens taken from the top of the tumor showed a well-differentiated adenocarcinoma. Under the diagnosis of cancer of the papilla of Vater, pancreaticoduodenectomy was performed. The first histological diagnosis was carcinoma in adenoma, but from the results of nucleus-gland ratio examined from 6 parts of the "adenoma", all of which were over 0.50, we finally concluded this case as de nove well-differentiated adenocarcinoma, and not carcinoma in adenoma. Thus, there is a possibility that past reports of adenoma or carcinoma in adenoma of the papilla of Vater might contain de novo well-differentiated adenocarcinoma.