Cystic pancreatic lesions: a simple imaging-based classification system for guiding management.

Cystic lesions of the pancreas are increasingly being recognized due to the widespread use of cross-sectional imaging. The initial evaluation of a pancreatic cyst should be directed toward exclusion of a pseudocyst. Patients with pseudocysts generally have a history of acute or chronic pancreatitis, whereas those with cystic tumors most often lack such a history. Several types of cystic lesions are encountered in the pancreas. Because of morphologic overlap at imaging, accurate characterization of these lesions can be difficult. Computed tomography and magnetic resonance imaging are excellent modalities for both initial detection and characterization of cystic pancreatic lesions. An imaging classification system for these lesions has been proposed that is based on the morphologic features of the lesion. This system can be helpful in characterizing lesions, narrowing the differential diagnosis, and making decisions regarding the treatment of affected patients. Endoscopic ultrasonography-guided aspiration and biopsy is useful in cases that are indeterminate at cross-sectional imaging or that require observation. RSNA, 2005.