Pancreatic Cystic Lesions

Pancreatic cysts are relatively rare lesions, and their diagnosis has increased with the widespread availability and use of cross-sectional imaging. In many cases pancreatic cysts are detected on imaging performed for another indication; however, they can also be seen in patients with symptoms such as abdominal pain or jaundice. Pancreatic cysts are reported to be found in 3% of computed tomography (CT) scans and 20% of magnetic resonance imaging (MRI) scans, and an increased prevalence is reported with advancing age. Patients with intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are at higher risk of pancreatic malignancy compared to the general population. The majority of pancreatic cystic lesions are nonneoplastic cysts, which are predominantly pancreatic pseudocysts (PPs) and are mostly seen as a local complication of pancreatitis. Neoplastic cysts of the pancreas are broadly categorized as mucinous and nonmucinous lesions, and the type of epithelial lining determines the risk of malignancy. Once a PP has been eliminated as a possibility, the next step is to determine the type of cyst based on cross-sectional imaging, aspiration cytology, and cyst fluid analysis ( Box 61.1 ).