Hepatocellular carcinoma with sarcomatous change arising after radiofrequency ablation for well-differentiated hepatocellular carcinoma

We report a case involving well-differentiated hepatocellular carcinoma (HCC) developing to HCC with sarcomatous changes after radiofrequency ablation (RFA). In a cirrhotic patient with both hepatitis B surface antigen and hepatitis C virus RNA, a well-differentiated HCC with a diameter of 2 cm was detected in segment IV of the liver. A combination of transcatheter arterial embolization and percutaneous ethanol injection (PEI) was performed and, after 8 months, PEI was performed for recurrent tumors. Fifteen months after the first treatment, a recurrent tumor measuring 3.5 cm in diameter was detected in segment IV, which was demonstrated as well-differentiated HCC by tumor biopsy, and treated by RFA. Although the treated lesion was reduced to 2.5 cm in diameter 6 months after RFA, the tumor rapidly enlarged to 6 cm in diameter 2 months later and progressed to lymph node metastasis. Aspiration biopsy showed spindle-shaped sarcomatoid cells with positive staining for both vimentin and keratin. The patient died of HCC progression 10 months after RFA. Autopsy findings showed both sarcomatoid cells and trabecular HCC cells. The sarcomatoid cells had metastasized to the lymph nodes and distant organs. This is the first case illustrating a sarcomatous HCC after RFA. Of interest, RFA may be related to the development of sarcomatous HCC.