CYST FLUID NB 70K CONCENTRATION AND LEUKOCYTE ESTERASE - 2 NEW MARKERS FOR DIFFERENTIATING PANCREATIC SEROUS TUMORS FROM PSEUDOCYSTS/

Cystic lesions of the pancreas include inflammatory pseudocysts, serou s cystadenomas, and mucinous tumors, some of which are malignant. Preo perative clinical and radiological parameters are unreliable and may r esult in incorrect diagnosis and inappropriate treatment. Cyst fluid a nalysis for cytology, viscosity, carcinoembryonic antigen, CA 72-4, an d CA 15-3 will distinguish mucinous from nonmucinous lesions and usual ly help in determining malignancy. Currently, there is no reliable met hod to differentiate inflammatory pseudocysts from serous cystadenomas . This distinction is important because the treatment of these two les ions is different; pseudocysts are either observed or drained, whereas serous tumors are usually resected. The tumor marker NB/70K was measu red in aspirated cyst fluid from 13 inflammatory pseudocysts and 11 se rous cystadenomas by a commercial immunoassay. Leukocyte esterase was measured using Chemstrip SG urine test strips and amylase and lipase o n a routine chemistry analyzer. The cyst fluid NB/70K concentration wa s significantly higher in pseudocysts (mean, 555 U/ml; range, 42-1,926 U/ml) than in serous cystadenomas (mean, 12 U/ml; range, 0-130 U/ml) and this difference was significant (p < 0.0002). Leukocyte esterase w as detected in 7 of 11 pseudocysts but was absent in 10 of 10 serous t umors (p = 0.002). Amylase and lipase values were generally higher in pseudocysts but these markers were unreliable due to marked outliers. Cyst fluid NB/70K and leukocyte esterase are promising markers to help differentiate pseudocysts from serous tumors on percutaneous aspirate s. When combined with previously reported cyst fluid parameters (amyla se, lipase, cytology, and amylase isoenzymes), these two cystic lesion s can be reliably distinguished.