EXPRESSION OF MUCIN-LIKE CARCINOMA-ASSOCIATED ANTIGEN IN THE CYST FLUID DIFFERENTIATES MUCINOUS FROM NONMUCINOUS PANCREATIC CYSTS

Objectives: Differential diagnosis of pancreatic cystic lesions may be difficult: the main problem is to distinguish mucinous neoplasms from nonmucinous cysts. We evaluated the usefulness of the mucin-like carc inoma-associated antigen (MCA) in the fluid of pancreatic cysts for de tecting mucinous neoplasms. Results were compared with those of CA 15- 3, carcinoembryonic antigen (CEA), and CA 72-4 fluid content, and cyto logy. Methods: Twenty-four pancreatic cyst fluids were collected from 10 pseudocysts, eight mucinous cystic tumors, and six serous cystadeno mas. Results: MCA was elevated in seven of eight mucinous tumors (sens itivity 87.5 %, specificity 100 %). A significant difference was found between MCA levels in mucinous neoplasms versus pseudocysts (p = 0.00 83) and serous cystadenomas (p 0.001). Mean MCA levels were higher (13 3.7 U/ml) in mucinous cystadenocarcinomas than in cystadenomas (37.5 U /ml). The sensitivity of CA 153, CEA, and CA 72-4 in detecting mucinou s neoplasms was 50, 87.5, and 87.5%, respectively, with a specificity of 94%, 44%, and 94%, respectively. Cytology showed mucinous epithelia l cells in only four of eight mucinous neoplasms, with a specificity o f 100%. Conclusions: These data suggest that MCA determination in the cyst fluid is a promising mew tumor marker for the preoperative diagno sis of mucinous cystic neoplasms of the pancreas.