Category II: Negative (for Malignancy)

Cysts of the pancreas display a wide spectrum of histology, including inflammatory (pseudocysts), benign (serous), premalignant (mucinous), and malignant (mucinous) lesions. Endoscopic ultrasonography (EUS) may offer a diagnostic tool through the combination of imaging and guided, fine-needle aspiration (FNA). The purpose of this investigation was to determine the most accurate test for differentiating mucinous from nonmucinous cystic lesions. The results of EUS imaging, cyst fluid cytology, and cyst fluid tumor markers (CEA, CA 72-4, CA 125, CA 19-9, and CA 15-3) were prospectively collected and compared in a multicenter study using histology as the final diagnostic standard. Three hundred forty-one (341) patients underwent EUS and FNA of a pancreatic cystic lesion; 112 of these patients underwent surgical resection, providing a histologic diagnosis of the cystic lesion (68 mucinous, 7 serous, 27 inflammatory, 5 endocrine, and 5 other). Receiver operator curve analysis of the tumor markers demonstrated that cyst fluid CEA (optimal cutoff of 192 ng/mL) demonstrated the greatest area under the curve (0.79) for differentiating mucinous vs. nonmucinous cystic lesions. The accuracy of CEA (88 of 111, 79%) was significantly greater than the accuracy of EUS morphology (57 of 112, 51%) or cytology (64 of 109, 59%) (P < 0.05). There was no combination of tests that provided greater accuracy than CEA alone (P < 0.0001). Of tested markers, cyst fluid CEA is the most accurate test available for the diagnosis of mucinous cystic lesions of the pancreas.

Cystic lesions of the pancreas are being recognized with increasing frequency and have become a more common finding in clinical practice because of the widespread use of advanced imaging modalities and the sharp drop in the mortality rate of pancreatic surgery. Consequently, in the past 2 decades, the nature of many cystic tumors in this organ has been better characterized, and significant developments have taken place in the classification and in our understanding of pancreatic cystic lesions. To provide an overview of the current concepts in classification, differential diagnosis, and clinical/biologic behavior of pancreatic cystic tumors. The authors' personal experience, based on institutional and consultation materials, combined with an analysis of the literature. In contrast to solid tumors, most of which are invasive ductal adenocarcinomas with dismal prognosis, cystic lesions of the pancreas are often either benign or low-grade indolent neoplasia. However, those that are mucinous, namely, intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, constitute an important category because they have well-established malignant potential, representing an adenoma-carcinoma sequence. Those that are nonmucinous such as serous tumors, congenital cysts, lymphoepithelial cysts, and squamoid cyst of pancreatic ducts have no malignant potential. Only rare nonmucinous cystic tumors that occur as a result of degenerative/necrotic changes in otherwise solid neoplasia, such as cystic ductal adenocarcinomas, cystic pancreatic endocrine neoplasia, and solid-pseudopapillary neoplasm, are also malignant and have variable degrees of aggressiveness.

EUS-guided FNA has the potential to provide diagnostic cytologic material from pancreatic lesions that are suspicious for malignancy. To determine the operating characteristics of EUS-FNA in the diagnosis of pancreatic adenocarcinoma and pancreatic neuroendocrine neoplasms (PENs). Retrospective analysis of a prospectively maintained database. Academic tertiary-care center. This study involved 559 patients undergoing evaluation of pancreatic masses or diffuse pancreatic parenchymal abnormalities. Performance characteristics of EUS-FNA of pancreatic adenocarcinoma and PEN. From January 1997 to December 2005, 737 patients undergoing initial EUS-FNA evaluation for a pancreatic mass were identified. In the final analysis, 559 patients with 560 FNA-sampled lesions were included. Overall, 442 lesions were pancreatic adenocarcinoma, and 40 were PEN. The sensitivity of EUS-FNA in the diagnosis of pancreatic adenocarcinomas and PENs was 77% (95% CI, 72.8%-80.8%) and 68% (95% CI, 50.8%-80.9%), respectively, using strict cytologic criteria. Reclassification of atypical and suspicious cytologies as diagnostic of malignancy resulted in a sensitivity of 93%, (95% CI, 90.9%-99.7%) in adenocarcinoma and 80% (95% CI, 63.9%-90.4%) in PEN. Tumor size, tumor location, and number of needle passes did not significantly influence diagnosis, but immediate cytologic evaluation was influential. Retrospective analysis at a single center. In a large, well-controlled study, EUS-FNA was found to be an accurate test (80%) for the detection of pancreatic adenocarcinoma by using aspiration cytology. The accuracy of the examination is significantly improved (94%) when atypical and suspicious samples are considered positive. Finally, only 2 to 3 FNA passes may be needed to achieve a good diagnostic yield. 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.