MUCIN-HYPERSECRETING TUMORS OF THE PANCREAS - ASSESSING THE GRADE OF MALIGNANCY PREOPERATIVELY

BACKGROUND: Mucin-hypersecreting tumor of the pancreas (MHST) is a uni que variant of pancreatic tumor, where mucin was excreted from the pat ulous orifice of the enlarged ampulla of Vater and the main pancreatic duct was dilated with excessive mucin, It is difficult to differentia te preoperatively between benign and malignant variants. PATIENTS AND METHODS: A total of 18 patients with an MHST were retrospectively revi ewed to identify possible indicators of malignancy, The 18 tumors cons isted of 9 benign lesions (hyperplasia or adenoma with mild to moderat e atypia), 2 borderline disorders (adenoma with severe atypia), and 7 malignant diseases (unequivocal adenocarcinoma). RESULTS: The age, sex , and site of origin demonstrated no significant difference among the three groups, One of the 9 patients with the benign lesion was diabeti c, while 4 of the 7 patients with the malignant variant were diabetic (P <0.05), All 9 benign lesions were confined to the side branch, whil e 4 of the 7 malignant diseases were located in the main pancreatic du ct (P <0.05), The mean greatest diameters of these three variants were 3.2 cm, 3.3 cm, and 6.6 cm, respectively, The mean greatest diameter of the main pancreatic duct in the 7 malignant disorders were larger t han in the 9 benign conditions (9.7 versus 5.4 mm, P <0.05), The mean diameter of the mural nodules in the 7 malignant tumors were larger th an in the 9 benign lesions (20.5 versus 5.1 mm, P <0.05), The serum an d mucin carcinoembryonic antigen and carbohydrate antigen 19-9 levels showed no substantial difference between the benign and malignant vari ants.CONCLUSIONS: The presence of diabetes, large tumors (25 cm), mark ed dilatation of the main pancreatic duct (greater than or equal to 10 mm), main pancreatic duct type, and large mural nodules (greater than or equal to 10 mm) is strongly suggestive of a malignant variant of t he MHST.