Q: A 29-year-old woman visits an ophthalmologist after noting a gradual decrease in visual acuity in her right eye over the last year. She plays tennis 3 times per week, eats a low-fat diet, and has a BMI of 24.4. She denies headache, trauma to the eye, or a family history of diabetes or multiple sclerosis, and does not take any medications. She is concerned because her father and paternal grandmother suffered from early blindness. On exam, the ophthalmologist notes several exudative hemangiomas on the retina of her right eye. A CT scan of her head reveals bilateral cerebellar cysts and medullary hemangioblastomas. This patient is at high risk of developing which of the following?