A case of conversion hepatectomy for huge hepatocellular carcinoma with adrenal metastasis and vascular invasion after atezolizumab-bevacizumab treatment.

We herein report a case of huge hepatocellular carcinoma (HCC) with adrenal metastasis and vascular invasion successfully treated by conversion hepatectomy after atezolizumab-bevacizumab treatment. A 77-year-old male patient with chest pain was admitted. He had a history of HCC treatment; however, the patient stopped receiving follow-up treatment based on his own decision. This time, he visited the emergency department of our hospital for the first time in 5 years. The tumor at the right lobe had grown into a lump with adrenal metastases and was 15 cm in diameter. It had invaded the inferior vena cava. Atezolizumab-bevacizumab treatment was selected for HCC treatment. Before starting treatment, his liver function was preserved (Child-Pugh A5). His alpha fetoprotein (AFP) and des-gamma-carboxyprothrombin (DCP) levels were 759.0 ng/mL and 5,681 mAU/mL, respectively. Atezolizumab-bevacizumab treatment resulted in a marked decrease in tumor marker levels and tumor staining. After nine courses of atezolizumab-bevacizumab treatment, it became difficult to continue the administration of bevacizumab because of proteinuria. Because the tumor had decreased in size and the tumor markers were in the normal range, we decided to perform conversion hepatectomy. The tumor was completely removed by combined resection of the diaphragm, and pathological analyses showed a complete response to atezolizumab-bevacizumab treatment. No viable tumor cells remained on histological analyses. The patient is doing well without any signs of recurrence at 3 months after conversion surgery.