The Value Of The Eus-Guided Fine-Needle Aspiration (Fna) In The Differential Diagnosis Of Intraductal Papillary Mucinous Tumors And Mucinous Cystadenoma

Introduction and Background: There are two pre-malignant pancreatic mucinous tumors: intraductal papillary mucinous tumor (IPMT) and the mucinous cystadenoma (MCA). In the first condition usually the main pancreatic duct is dilated, and the other one is macrocystic, uni ou multilocular and envolved by a fibrous capsule. It's hard to obtain the correct diagnosis in tumors less than 3.0 cm. Our purpose was to analyse the value of the EUS-FNA for the differential diagnosis of both neoplasms and to identify malignancy-predicting criteria in these cystic lesions. Patients and Methods: We prospectively analysed the clinicopathologic data of 50 patients [37 women; mean age 63 (11-89) years] suffering from pancreatic cystic lesions who were referred to EUS-FNA between 1999 and 2005 at a single Center. The main reason for the procedure was incidental finding (24), abdominal pain (18), acute pancreatitis (4) and colestasis (4). The ultrasonographic features of the cystic collections taken into account were location (main duct, branch duct or parenchima), number, size, topography and the presence of mural nodules. The final diagnosis was obtained by surgery in 40 cases and by clinical follow-up after FNA in 10 cases. Results: Malignancy was detected in 5 (10%) cases. The final diagnoses were IPMT (42), mucinous cystadenoma (8) and cystadenocarcinoma (1). The disease was restricted to the main pancreatic duct (27), to the branch ducts (12), to the parenchima (8) or to both ducts (3). The mean size of the cysts was 3.2 (0.7-11.6) cm. Pancreatic head was affected in 29 (58%) cases. All malignancies harbored mural nodules. Overall, nodules were detected in 15 (30%) patients. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the FNA to detect malignancy were, respectively, 60%, 100%, 100%, 95.7% and 96%. The accuracy to the differential diagnosis between IPMT and mucinous cystadenoma obtained by means of the echoendoscopic assessment was 87.6%. Conclusion: EUS-guided FNA makes possible the differential diagnosis between IPMT and MCA. However, the presence of mural nodules is more accurate to confirm the malignancy than FNA, which reveals a very low sensitivity when solely the cytopathology is taken into account.