Villous adenoma of the ampulla of Vater is a rare tumor. It is a deceptive tumor because it is a premalignant lesion and biopsies of the lesion are false negative in 25% to 56% of patients. The primary focus of this report is 23 of 30 patients with villous adenoma of the ampulla of Vater who underwent Whipple operations. Paraffin blocks from 22 patients were available. In eight patients, blocks of the biopsies and the corresponding resected specimens were available. Immunohistochemical studies using antibodies to p53 and Ki-67 were performed to determine whether accumulation of these antibodies in the biopsy specimens would identify false negative biopsies. There was one operative death. The 2-, 5-, and 10-year survival rates for the 22 patients surviving a Whipple operation were 74%, 57%, and 35%, respectively. Three patients died of cancer. The mean p53 expression index was increased in adenomas to 88 (P = 0.001) and in carcinomas to 114 (P = 0.01), compared with 12.6 for normal ampullary epithelium adjacent to tumor. Significant differences in the Ki-67 proliferation index were noted between normal adjacent epithelium (13%), adenoma (34%, P = 0.0002), and carcinoma (53%, P = 0.034), as well as between adenomatous epithelium and carcinoma (34% vs. 53%, P = .012). Villous ampullary adenocarcinoma was present in 65% of patients with villous adenoma (87% if patients with carcinoma in situ in resected specimens are included). Because of the high false negative rate of ampullary biopsies, and the inability to accurately stage these lesions, we recommend pancreaticoduodenectomy in most patients. Studies with p53 and Ki-67 markers suggest that they may be helpful in the recognition of ampullary villous cancer not identified on routine biopsies.
- Villous adenoma
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