Variability in cyst fluid carcinoembryonic antigen level, fluid viscosity, amylase content, and cytologic findings among multiple loculi of a pancreatic mucinous cystic neoplasm.

The procedure of percutaneous aspiration and analysis of cyst contents has been advocated to provide a preoperative diagnosis of pancreatic cystic lesions (pseudocysts and cystic tumors), but it is not known whether variation in the contents of separate loculi of a multilocular neoplasm might misrepresent the identity of the tumor. The authors measured the cyst fluid carcinoembryonic antigen (CEA) level, fluid viscosity, and amylase content and performed cytologic analysis on aspirates rates from ten different loculi of a single mucinous cystic neoplasm of the pancreas. The CEA levels were highly variable (median, 6,326 ng/mL; range, 962-64,670 ng/mL) but in all cases were diagnostic of a mucinous tumor. Fluid relative viscosity values were also variable (median, 2.4; range, 1.3-10+) but diagnostic in eight of nine aspirates. The amylase content in all of the loculi was low (< 91 U/L), and values were consistent with a cystic tumor. Cytologic analysis showed diagnostic mucin-secreting epithelial cells in nine of ten loculi. Although cytologic examination was nondiagnostic in one loculus, there were no false-positive results for malignancy. The combination of all four tests would not have resulted in misclassification of any of the tumors. The authors conclude that the characteristics of the contents of different loculi of pancreatic cystic neoplasms may be variable, but the use of a combination of tests still ensures accurate diagnosis.