Granulomatous reaction in hepatic inflammatory angiomyolipoma after chemoembolization and spontaneous rupture

A 77-year-old Japanese woman was transported to a nearby hospital due to sudden abdominal pain and transient loss of consciousness. Abdominal computed tomography (CT) suggested hemoperitoneum and hepatic nodule. She was conservatively treated. Contrast-enhanced CT two months later revealed an increased mass size, and the enhancement pattern suggested the possibility of hepatocellular carcinoma (HCC). Under a clinical diagnosis of HCC, transcatheter arterial chemoembolization (TACE) was performed. A subsequent imaging study revealed that most of the lipiodol used for the embolization was washed out. Therefore, surgical resection was performed. Histologically, the nodule contained numerous inflammatory cells including small lymphocytes, plasma cells and macrophages. Notably, epithelioid granulomatous features with multinucleated giant cells were observed in both the nodule and background liver. Some of the multinucleated giant cells contained oil lipid. Among the infiltrating inflammatory cells, spindle-shaped, histiocytoid or myoid tumor cells with eosinophilic cytoplasm were found. The tumor cells were positive for Melan A and HMB45. The nodule contained many IgG4-positive plasma cells; these were counted and found to number 72.6 cells/HPF (range: 61-80). The calculated IgG4:IgG ratio was 33.2%. The nodule was finally diagnosed as previously ruptured inflammatory angiomyolipoma modified by granulomatous reaction after TACE.