['The preoperative diagnosis of branch duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas can be very difficult, since low-risk and high-risk lesions can be difficult to differentiate even after cytological analysis. The purpose of this study was to evaluate the preoperative diagnostic value of endoscopic ultrasonography (EUS) in differentiating low-risk and high-risk IPMNs.', 'We retrospectively identified 36 patients who underwent preoperative EUS for branch duct IPMNs. The pathological diagnosis after surgical resection was low-grade dysplasia (n = 26), moderate dysplasia (n = 1), high-grade dysplasia or carcinoma in situ (n = 5), and invasive carcinoma (n = 4). We divided the patients into two groups: low risk (low-grade dysplasia or moderate dysplasia) and high risk (high-grade dysplasia or carcinoma). We focused on the diameter of the cystic dilated branch duct, the main pancreatic duct, and the mural nodule as measured using the EUS findings.', 'The cystic dilated branch duct diameter (31.5 mm vs. 41.9 mm, P = 0.0225) was significantly correlated with low-risk and high-risk IPMNs, but the main pancreatic duct diameter (5.37 mm vs. 5.44 mm, P = 0.9418) was not significantly correlated with the low-risk and high-risk IPMNs. The mural nodule diameter of the papillary protrusions (4.3 mm vs. 16.4 mm, P < 0.0001) and the width diameter of the mural nodule (5.7 mm vs. 23.2 mm, P < 0.0001) were significantly correlated with low-risk and high-risk IPMNs.'] Do endoscopic ultrasonographic findings predict the risk of carcinoma in branch duct intraductal papillary mucinous neoplasms of the pancreas?