Mucinous vs. non-mucinous pancreatic cysts: diagnostic keys on CT and MRI.

The prevalence of incidentally detected pancreatic cystic lesions has increased substantially with the widespread use of high-resolution CT and MRI. Differentiating mucinous from non-mucinous cystic lesions is a central diagnostic task, as mucinous lesions are associated with a risk of malignant transformation and distinct management pathways. In clinical practice, this distinction is primarily driven by imaging findings. This review summarizes the key CT and MRI features that allow differentiation between mucinous and non-mucinous pancreatic cystic lesions, with a focus on reproducible criteria applicable in routine practice. Particular emphasis is placed on the assessment of communication with the main pancreatic duct, lesion morphology, wall thickness and enhancement pattern, internal architecture, calcification pattern, cyst multiplicity, and associated ductal or parenchymal abnormalities. Common diagnostic challenges are discussed, including atypical lesion location, atypical presentation and imaging overlap between cystic lesions. These scenarios illustrate the limitations of relying on a single imaging criterion and highlight the need for a comprehensive, pattern-based approach. The review also underscores the importance of integrating imaging findings with patient demographics, lesion distribution, clinical context, and longitudinal imaging behavior. In selected cases, CT and MRI may not allow definitive classification, and diagnostic uncertainty should be explicitly acknowledged to guide appropriate multidisciplinary decision-making. Emerging imaging techniques, including artificial intelligence algorithms, are briefly addressed. While preliminary results are encouraging, current evidence remains insufficient to support routine clinical implementation. At present, systematic analysis of CT and MRI findings, supported by multidisciplinary expert interpretation, remains the cornerstone for differentiating mucinous from non-mucinous pancreatic cystic lesions.