Diagnostic Accuracy of the Initial Endoscopy for Ampullary Tumors

BACKGROUND/AIMS: Ampullary tumors come in a wide variety of malignant forms. We evaluated the diagnostic accuracy of endoscopy for ampullary tumors, and analyzed the causes of misdiagnosis. METHODS: We compared endoscopic imaging and biopsy results to final diagnoses. Types of endoscope, numbers of biopsy specimens taken, and final diagnoses were evaluated as possible factors influencing diagnostic accuracy. RESULTS: Final diagnoses were 19 adenocarcinomas, 18 normal or papillitis, 11 adenomas, two adenomyomas, one paraganglioma, and one neuroendocrine tumor. The diagnostic accuracy of endoscopic imaging or the initial biopsy was identical (67.3%). At least one test was concordant with the final diagnosis in all except two cases. Compared with the final diagnosis, endoscopic imaging tended to show more advanced tumors, whereas the initial biopsy revealed less advanced lesions. The diagnostic accuracy of the initial biopsy was influenced by the type of endoscope used and the final diagnosis, but not by the number of biopsies taken. CONCLUSIONS: Endoscopy has limited accuracy in the diagnosis of ampullary tumors. However, most cases with concordant endoscopic imaging and biopsy results are identical to the final diagnosis. Therefore, in cases where both of these tests disagree, re-evaluation with a side-viewing endoscope after resolution of papillitis is required.