Hepatic Xanthogranuloma that Originated from a Liver Cyst and Mimicked a Malignant Tumor.

BACKGROUND/AIM: Hepatic xanthogranuloma is a very rale disease and formation process is unknown. CASE REPORT: A 69-year-old woman previously diagnosed as simple liver cyst. Two years before, a 36-mm liver cyst was found in segment 5, while one year later, the hemorrhagic cyst was 40 mm in diameter and a thin septum had formed. The most recent T1-weighted magnetic resonance imaging (MRI) showed a regular 21-mm hepatic mass with a hyperintense 11-mm center and a hypointense periphery. Peripheral enhancement was seen on gadolinium enhanced MRI. Hepatobiliary cystadenoma or cystadenocarcinoma was suspected because of wall thickness and slight enhancement. Microscopic examination following laparoscopic partial liver resection revealed fibroblasts, dense collagen fibers, and a double layer of hemosiderin-laden as well as foamy macrophages attached to the fibrous capsule. CONCLUSION: The patient was diagnosed with a hepatic xanthogranuloma that originated from a hemorrhagic liver cyst. Intracystic hemorrhage may be one of the reasons for hepatic xanthogranuloma formation.