Atezolizumab plus bevacizumab-induced intratumoral hemorrhage in a patient with rib metastasis from unresectable hepatocellular carcinoma

Recently, combination therapy with atezolizumab, a humanized monoclonal antiprogrammed death ligand-1 antibody, and bevacizumab, has become available for treatment of unresectable hepatocellular carcinoma (HCC). We herein report a 73-year-old man with advanced stage HCC who developed fatigue during treatment with atezolizumab–bevacizumab combination therapy. Computed tomography identified intratumoral hemorrhage within the HCC metastasis to the right fifth rib metastasis of HCC, which was confirmed on emergency angiography of the right 4th and 5th intercostal arteries and some branches of the subclavian artery confirmed intratumoral hemorrhage, following which transcatheter arterial embolization (TAE) was performed to achieve hemostasis. He continued to receive atezolizumab-bevacizumab combination therapy after TAE, and no rebleeding was seen. Although uncommon, rupture and intratumoral hemorrhage in the HCC metastasis to the ribs can cause life-threatening hemothorax. However, to our knowledge, no previous cases of intratumoral hemorrhage in HCC during atezolizumab–bevacizumab combination therapy have been reported. This is the first report of intratumoral hemorrhage with the combination therapy of atezolizumab and bevacizumab, which was successfully controlled by TAE. Patients receiving this combination therapy should be observed for intratumoral hemorrhage, which can be managed by TAE if it does occur.