Differential diagnosis for intrahepatic biliary cystadenoma and hepatic simple cyst: significance of cystic fluid analysis and radiologic findings.

GOALS: This study evaluated the significance of cystic fluid analysis and radiologic findings in the differential diagnosis of biliary cystadenomas (BCA) and hepatic simple cysts (HSCs).

BACKGROUND: BCA are premalignant lesions. The treatment of choice is surgical excision. It is important to differentiate BCA from HSCs because they have different clinical significances and treatment plans. However, it is difficult to preoperatively differentiate a BCA from a HSC.

STUDY: This retrospective study was done with 31 patients suffering from pathologically diagnosed BCA or HSC. All patients underwent surgery between May 1995 and June 2008 at a single institution and had cystic fluid analysis preoperatively or intraoperatively.

RESULTS: We discovered no statistically significant differences in cystic fluid carbohydrate antigen 19-9 (CA 19-9) levels or carcinoembryonic antigen levels when comparing BCA (n=17) and HSCs (n=14). BCA were significantly more frequently associated with female sex (17/17 vs. 10/14, P=0.032), presence of a septum (16/17 vs.5/14, P=0.001), and septal thickening (8/17 vs. 1/14, P=0.021). All 3 cases with calcifications belonged to the BCA group, but sample size was too small to demonstrate statistical significance. There were no statistically significant differences in other clinical and radiologic findings including age, presence of symptoms, serum tumor markers, serum chemistry, size, location, lobulation, septal enhancement, wall enhancement, wall thickening, mural nodule, or biliary dilatation.

CONCLUSIONS: Cystic fluid carbohydrate antigen 19-9 levels and carcinoembryonic antigen levels were not useful for differential diagnosis of BCA vs. HSC. BCA were more common than HSCs in females, patients with a septum, and patients with septal thickening.