Aims: Biopsies from the ampulla of Vater and the common bile duct often pose diagnostic challenges. The aim of this study was to investigate the expression patterns of HMGA1, HMGA2, β-catenin and p53 in biopsy specimens, in order to evaluate the potential diagnostic value of these proteins in differentiating adenocarcinoma from reactive atypia or adenoma.
Methods and results: Forty-eight biopsies (10 from the common bile duct and 38 from the ampulla) were selected for immunohistochemical studies; they included 14 cases of reactive atypia, 12 adenomas, and 22 adenocarcinomas. Expression of HMGA1 was seen in 21% of the reactive atypia cases, 42% of adenomas, and 91% of adenocarcinomas. HMGA2 was positive in 14% of reactive atypias, 42% of adenomas, and 86% of adenocarcinomas. The staining intensity of HMGA1 and HMGA2 was also significantly higher in adenocarcinomas than in adenomas or reactive atypias. Interestingly, coexpression of HMGA1 and HMGA2 was found in 86% of adenocarcinomas, 0% of reactive atypias, and 8% of adenomas. p53 and β-catenin expression seemed not to provide additional value for discriminating adenocarcinoma from reactive atypia or adenoma.
Conclusions: HMGA1 and HMGA2 might serve to discriminate between reactive atypia, adenoma and adenocarcinoma in ampulla and common bile duct biopsies.
© 2013 Blackwell Publishing Ltd.