Imaging classification of pancreatic cystic lesions: a radiologist's guide

Pancreatic cystic lesions (PCLs) are increasingly encountered in clinical practice owing to the widespread use of high-resolution cross-sectional imaging. These lesions comprise a heterogeneous group of entities ranging from benign cysts to pre-malignant neoplasms and invasive cancers, making accurate characterization essential for appropriate patient surveillance and therapeutic management. Imaging plays a pivotal role in lesion detection, differential diagnosis, and assessment of malignant potential. This review presents a practical imaging-based classification of PCLs founded on lesion morphology, relationship to the pancreatic ductal system, enhancement patterns, and associated imaging features. Using a stepwise diagnostic approach, pancreatic cystic lesions are categorized according to their increasing risk of malignancy into non-neoplastic cysts, serous cystic neoplasms, mucinous cystic lesions, and cystic degeneration of solid pancreatic tumors. Characteristic imaging findings, relevant differential diagnostic considerations, and imaging features associated with increased malignant potential are comprehensively reviewed, with particular emphasis on the role of MRI and MR cholangiopancreatography (MRCP) in lesion characterization. A structured pattern-recognition flowchart is proposed to facilitate routine image interpretation and enhance diagnostic confidence. In addition, a practical reporting template is presented to promote standardized assessment and effective communication within multidisciplinary teams. Emerging techniques, including diffusion-weighted imaging, quantitative MRI biomarkers, radiomics, artificial intelligence, and molecular analysis of cyst fluid, are discussed as promising tools for improving diagnostic accuracy and refining risk stratification. By emphasizing readily recognizable imaging features and a systematic diagnostic workflow, this review provides radiologists with a practical and clinically applicable framework for the evaluation, diagnosis, risk assessment, and multidisciplinary management of pancreatic cystic lesions.