Cystic Neoplasms of the Pancreas

The increasing use of abdominal imaging studies such as abdominal ultrasound, computed tomography (CT) scan, and magnetic resonance imaging (MRI) has contributed to the incidental detection of pancreatic cysts, some of which may be malignant and others premalignant or benign. Overall in asymptomatic patients, 2.5% have pancreatic cysts, and the number increases to 10% in those older than 70 years. Once detected, the clinician should not ignore the finding even in the asymptomatic patient. The topic has thus assumed tremendous importance, and various guidelines are recently proposed to manage the problem.

The three most common epithelial tumors of the pancreas are serous cystic neoplasms (SCNs), mucinous cystic neoplasm (MCNs), and intraductal papillary mucinous neoplasm (IPMN). The less frequent are the cystic endocrine, solid, and pseudopapillary tumors. Pancreatic cysts can be classified as mucinous or nonmucinous, based on the nature of the cyst content. The mucinous cysts are either malignant at the time of initial diagnosis or have a higher potential for malignant progression as compared with serous cysts.

The best imaging modalities to identify the nature of these cysts are multidetector CT and MRI. The accuracy of providing the correct histologic diagnosis by these modalities is low and ranges from 40% to 60%. Diagnostic endoscopic retrograde cholangio-pancreatography (ERCP) has very little role, but endoscopic ultrasound (EUS) plays a major role in characterizing the cysts and in performing tests in the cyst aspirate.