Supplementary Material for: Pulmonary metastasectomy after RFA of hepatocellular carcinoma

Introduction
Single distant metastases after radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) are rare. There are no guidelines for treating patients without liver tumors after resecting lung metastases.
Case presentation
Here, we report a patient with hepatocellular carcinoma recurring as a single lung metastasis fourteen months after RFA. A 76-year-old woman with primary biliary cholangitis without hepatitis B virus or hepatitis C virus infection had been treated by RFA for a single 16-mm-sized HCC lesion in liver S8. Fourteen months thereafter, despite lack of intrahepatic recurrence, a single new 26-mm-sized mass was found in S10 of the right lung. The patient underwent right lower lobectomy. The histopathological diagnosis was HCC metastasis. Because no residual disease could be found, she was followed up without any additional treatment after surgery. She remains alive with no signs of recurrence three years later.
Conclusion
HCC patients who relapse with lung metastases but without intrahepatic recurrence after RFA are extremely rare, especially when RFA is used to treat HCC lesions <30 mm. However, it should be noted that, although rare, HCC may recur in the form of extrahepatic metastases after RFA. Furthermore, it is suggested that, as in the presently-described case, at least some patients without intrahepatic recurrence whose lung metastases are completely resected have a good prognosis even without additional treatment for HCC.