Reduction of bleeding by cabozantinib in metastatic renal cell carcinoma with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic disorder characterized by refractory recurrent epistaxis and gastrointestinal bleeding. Recent studies have reported the hemostatic effects of tyrosine kinase inhibitors on HHT-related bleeding. A 67-year-old man with HHT underwent laparoscopic radical nephrectomy for right renal cell carcinoma discovered during an investigation of anemia. Five years after surgery, pancreatic metastasis with biliary dilatation was found on computed tomography. After a biliary stent was inserted, the patient was treated with cabozantinib plus nivolumab. His hemoglobin level significantly improved from 4.8 g/dL to a maximum of 14.7 g/dL, and transfusion frequency reduced from five to one per 5 months. Despite tumor reduction after 6 months of treatment, the patient developed acute cholangitis because of biliary hemorrhage, which ultimately resulted in hepatic failure and death. This case is the first to indicate the potential of the tyrosine kinase inhibitor cabozantinib to control bleeding and tumor progression in patients with metastatic renal cell carcinoma with HHT-related bleeding.