Role of endoscopic ultrasound in the diagnosis of intraductal papillary mucinous neoplasms: Correlation with surgical histopathology

Background & Aims: intraductal papillary mucinous neoplasms (IPMNs) are precancerous tumors characterized by dilation of the main pancreatic duct, its side branches, or both. The purpose of this study was to evaluate the role of endoscopic ultrasound (EUS) in differentiating benign and malignant IPMNs. Methods: We identified all patients between July 1996 -November 2005 who underwent preoperative EUS for IPMNs. Malignancy was defined as the presence of invasive carcinoma; all other neoplasms were considered benign. The results of EUS and EUS-guided fine-needle aspiration (EUS-FNA) were compared with corresponding histopathology. Results: Seventy-four patients (38 male; mean age, 65 years) with 21 (28%) malignant and 53 (72%) benign IPMNs were identified. Sixty-five (88%) underwent EUS-FNA. Compared with benign tumors, patients with malignant IPMNs were more likely to be older (P=.011), present with jaundice (P=.03) or weight loss (P=.03), and have EUS features of a dilated main pancreatic duct (P=.0001), solid lesion (P=.0001), pancreatic ductal filling defects (P=.03), or thickened septa within any cyst (P=.02). The sensitivity, specificity, and accuracy of EUS-FNA for the diagnosis of malignancy were 75% (95% confidence interval [CI], 53%-89%), 91% (95% CI, 79%-97%), and 86% (95% CI 76%-93%), respectively. Cyst or pancreatic duct fluid carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 did not differ between groups. Conclusions: Older age, jaundice and weight loss, and EUS features of a solid lesion, dilated main pancreatic duct, ductal filling defects, and thickened septa are predictive of malignancy in patients with IPMNs. EUS-FNA cytology is helpful, but cyst fluid CEA and CA 19-9 are of limited value to differentiate malignant from benign IPMNs.