Background/goals: The endoscopic treatment of ampullary adenomas is established; however, the false-negative rate of endoscopic biopsy for carcinoma is 20% to 30%, and it remains uncertain whether identifiable features predict malignancy. Our aim in this study was to evaluate the predictable factors of malignancy in ampullary adenomas on endoscopic biopsy.
Study: Ninety-one subjects diagnosed with ampullary adenoma on endoscopic biopsy were confirmed after endoscopic or surgical resection of ampullary lesions between 1995 and 2011 respectively. Clinical, laboratory, radiologic, and endoscopic findings were compared between patients with adenoma and carcinoma after resection. We examined the predictors of malignancy in ampullary adenoma on endoscopic biopsy.
Results: The malignancy rate in ampullary adenomas on endoscopic biopsy was 26.4%. Univariate analysis revealed that presence of symptoms, villous components, high-grade dysplasia (HGD), papilla enlargement on computed tomography, duct dilatation on radiologic imaging, bilirubin>2 mg/dL, aspartate aminotransferase>40 IU/L, alanine aminotransferase>40 IU/L, and alkaline phosphatase>90 U/L were associated with malignancy in patients over 65 years of age. HGD [odds ratio, 6.86 (95% confidence interval, 1.58-29.79)] and ductal dilatation [odds ratio, 11.12 (95% confidence interval, 2.27-54.37)] were independently associated with malignancy in multivariate analysis. The sensitivity and negative predictive value for ≥1 risk factors were 95.83% and 96.77%, respectively. The presence of 2 risk factors resulted in a high specificity (96%) and positive predictive value (84%) for malignancy.
Conclusions: HGD and ductal dilatation are significant predictors of malignancy in ampullary adenomas. When these risk factors are present, precautions should be taken in the consideration of malignancy in patients with ampullary adenoma.