Interobserver agreement among endosonographers for the diagnosis of neoplastic versus non-neoplastic pancreatic cystic lesions

Background: The aim of this study was to evaluate the degree of agreement among endosonographers for EUS diagnosis of neoplastic versus non-neoplastic pancreatic cystic lesions and the specific type of cystic lesion. Methods: Videotapes of EUS procedures from 31 consecutive cases of a range of histopathologically proven lesions, including mucinous cystic neoplasm, serous cystadenoma, neuroendocrine tumor, intraductal papillary mucinous tumor, and pseudocyst, were used to make a study video-tape, which was reviewed by 8 experienced endosonographers. The reviewers, blinded to clinical and surgical histopathology results, reviewed each case for the presence or absence of the following features: abnormality of pancreatic duct and parenchyma, margins, solid component, debris, and septations. They were asked to identify each lesion as neoplastic or non-neoplastic and to give a specific diagnosis for each lesion. Results: There was fair agreement between endosonographers for diagnosis of neoplastic versus non-neoplastic lesions (K = 0.24). Agreement for individual types of lesions was moderately good for serous cystadenomas (K = 0.46) but fair for the remainder. Agreement was moderately good for presence or absence of solid component (K = 0.43); fair for presence or absence of abnormal pancreatic duct (K = 0.29), debris (K = 0.21), and septations (K = 0.30); and slight for presence or absence of margins (K = 0.01) and abnormal pancreatic parenchyma (K = 0.01). Accuracy rates of EUS for the diagnosis of neoplastic versus non-neoplastic lesions ranged from 40% to 93%. Conclusions: There is little more than chance interobserver agreement among experienced endosonographers for diagnosis of neoplastic versus non-neoplastic, specific type, and EUS features of pancreatic cystic lesions.