Evaluation of cyst fluid analysis in the diagnosis of pancreatic cysts.

The pre-operative differential diagnosis of pancreatic cystic lesions is often difficult because of the lack of reliable clinical or radiological criteria. In order to improve the pre-operative recognition of these lesions, we performed cyst fluid analysis for enzymes (amylase and lipase), tumour markers (CEA, CA 19-9, CA 125, CA 72-4), and cytology in 52 pancreatic cysts. The cases included 21 pseudocysts, 12 mucinous cystic neoplasms, 7 ductal carcinomas, 7 benign lesions, and 5 rare malignancies observed from 1989 to 1994. Cyst fluid amylase, lipase, CEA, and CA 19-9 were variable and not discriminant between the groups. CA 125 fluid levels were high in 63% of malignant cysts. CA 72-4 fluid levels were significantly higher in mucinous cystic tumours than in pseudocysts (p < 0.0001), showing 95% specificity in detecting mucinous or malignant cysts. Cytology showed a sensitivity of 61% and a specificity of 100%. CA 72-4 determination raised the sensitivity of cytology to 92% in detecting mucinous or malignant cysts. This study confirms the low sensitivity of cytologic examination and low amylase specificity in distinguishing cystic neoplasms from pseudocysts. Cyst tumour markers assay is useful to improve the sensitivity of cytology, and CA 72-4 shows the best specificity in detecting (pre)malignant neoplasms.