Differential diagnosis of cystic tumors of the pancreas by endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: Generally, cystic tumors are divided into two categories: neoplastic cystic tumors and non-neoplastic cystic (NNC) tumors. Neoplastic cystic tumors include mucinous cystic neoplasm (MCN), intraductal papillary-mucinous neoplasm (IPMN), and serous cystic neoplasm (SCN). MCNs and IPMNs have the potential to progress to a malignant state, whereas SCNs are known for their almost benign behavior. Thus, in order to make management decisions, it is important to distinguish between potentially malignant (MCN and IPMN), and benign (SCN and NNC) tumors. The aim of this study was to retrospectively investigate the value of endoscopic ultrasonography (EUS) for the differential diagnosis of cystic tumors of the pancreas.

PATIENTS AND METHODS: A total of 76 patients with cystic tumors of the pancreas were preoperatively examined by EUS. Eight cases were MCNs, 45 were IPMNs, 13 were SCNs, and 10 were NNC tumors. The EUS findings relevant to distinguishing between potentially malignant and benign were analyzed statistically.

RESULTS: All patients with MCNs were female and all these tumors were located in the pancreatic body/tail. IPMN, however, occurred predominantly in men, and in the pancreatic head. Eight of 11 monolocular cystic tumors were NNC in nature. Eleven of 13 SCNs included microcystic areas within the tumors. All MCNs were round in appearance, whereas 93 % of IPMNs were not round in appearance. Mural nodules were present in 25 % of MCN and 38 % of IPMN cases. In univariate analysis, age, tumor size, locularity, the number of cystic formation, cystic component, and appearance were significant variables. In multivariate analysis, locularity and cystic component were important for differential diagnosis of potentially malignant cystic tumors.

CONCLUSIONS: The characteristics of cystic tumors of the pancreas revealed by EUS are useful for their differential diagnosis.