BELZUTIFAN FOR TREATMENT OF GIANT RETINAL HEMANGIOBLASTOMA WITH EXTRASCLERAL EXTENSION ASSOCIATED WITH VON HIPPEL-LINDAU SYNDROME.

Purpose: To describe the clinical response and safety profile of the novel HIF-2ɑ inhibitor belzutifan in treating a giant retinal hemangioblastoma with extrascleral extension associated with von Hippel-Lindau syndrome.

Methods: A 71-year-old woman with Von Hippel-Lindau syndrome presented with a giant retinal hemangioblastoma with extrascleral extension in her only remaining eye. She had no light perception in the right eye and intraocular pressure was 48. She requested enucleation because of chronic pain, but because of concern for significant bleeding given the size of the neoplasm, a trial of belzutifan was initiated.

Results: Within 3 months of treatment initiation, the patient reported an 80% reduction in pain. Magnetic resonance imaging showed 30% reduction in longest tumor diameter. Dose adjustments were guided by serum hemoglobin levels, allowing the patient to remain on the medication for over a year with continued tumor regression on MRI and avoid enucleation.

Conclusion: Retinal hemangioblastoma with extrascleral extension is exceedingly rare and its treatment is complex, often requiring enucleation or external beam radiotherapy. This report demonstrates the use of belzutifan to safely and successfully reduce ocular tumor burden of complicated retinal hemangioblastoma with extrascleral extension, ultimately decreasing the need for enucleation.