Radiological differential diagnoses and radiopathological correlations of pancreatic cystic lesions associated with pancreatic tumors

Recent advancements in radiological imaging have led to an increasing detection of pancreatic cystic lesions, thereby intensifying the challenge of differential diagnosis within radiology practice, with a reported prevalence of 49.1%. While some imaging findings of pancreatic cystic lesions are well-established, there exist numerous lesions for which radiological findings cannot be definitively determined. The purpose of our study is to determine the radiological characteristics of cystic lesions, identify radiological indicators that can aid in their differential diagnosis through radiopathological correlation, and demonstrate the accuracy of imaging in diagnosing pancreatic cystic lesions in cases of pancreatic tumors. Our study included 101 patients diagnosed with pancreatic tumors who underwent pancreatic resection and had cysts detected in their imaging between January 2012 and December 2022. Radiological evaluations were conducted for 130 pancreatic cystic lesions, and radiopathological correlations were individually established for each cyst. Using pathology as the gold standard, the diagnostic performance of radiology was calculated. The most common cystic lesions accompanying pancreatic tumors were retention cysts and ductal dilations (53.8%). It was found that retention cysts and ductal dilations were smaller in size, more frequently associated with pancreatic tumors (with no normal pancreatic tissue between the pancreatic tumor and cystic lesions), and often multiple compared to other cysts. Simple mucinous cysts were relatively larger in size and were shown to be associated with pancreatic tumors, with this relationship being a critical parameter in distinguishing these lesions from squamoid cysts of the pancreatic duct. The rate of incomplete pancreas divisum in squamoid cysts of pancreatic ducts was determined to be 66.7%. The diagnostic accuracy of CT in cystic lesions of the pancreas was 85.2%, while MRI had an accuracy of 88.3%. In pancreatic cystic lesions, the sensitivity of radiology ranged from 55.6% to 100%, specificity ranged from 91.7% to 100%, positive predictive value ranged from 57.1% to 100%, and negative predictive value ranged from 96.5% to 100%.