Retinal capillary hemangioblastoma (angiomatosis retinae, previously known as retinal capillary hemangioma) is a rare autosomal dominant condition with a reported incidence of 1 in 40,000. Typically, patients are diagnosed in the second to third decades of life, although retinal lesions may be present at birth. The retinal capillary hemangioblastoma appears as a red to orange tumor arising within the retina with large-caliber, tortuous afferent and efferent retinal blood vessels (Fig 18-3). Associated yellow-white retinal and subretinal exudates that have a predilection for foveal involvement may appear. Exudative detachments often occur in eyes with hemangioblastomas. Atypical variations include hemangiomas arising from the optic disc, which may appear as encapsulated lesions with or without pseudopapilledema, and in the retinal periphery, where vitreous traction may elevate the tumor from the surface of the retina, giving the appearance of a free-floating vitreous mass. Fluorescein angiography of retinal capillary hemangioblastomas demonstrates a rapid arteriovenous transit, with immediate filling of the feeding arteriole, subsequent filling of the numerous fine blood vessels that constitute the tumor, and drainage by the dilated venule. Massive leakage of dye into the tumor and vitreous can occur.
When a capillary hemangioblastoma of the retina occurs as a solitary finding, the condition is generally known as von Hippel disease. This condition is familial in about 20% of cases and bilateral in about 50%. The lesions may be multiple in 1 or both eyes. If retinal capillary hemangiomatosis is associated with a cerebellar hemangioblastoma, the term von Hippel–Lindau syndrome is applied. The gene for von Hippel–Lindau syndrome has been isolated on chromosome 3. A number of other tumors and cysts may occur in patients with von Hippel–Lindau syndrome. The most important of these lesions are cerebellar hemangioblastomas, renal cell carcinomas, and pheochromocytomas. Genetic screening now allows for subtyping of patients with von Hippel–Lindau to determine the risk for systemic manifestations of the disease. When this diagnosis is suspected, appropriate genetic consultation and screening are critical for long-term follow-up of ocular manifestations and the associated systemic complications. Screening for systemic vascular anomalies (eg, cerebellar hemangioblastomas) and malignancies (eg, renal cell carcinoma) may reduce mortality, while aggressive screening for and early treatment of retinal hemangioblastomas may reduce late complications of exudative detachment and improve long-term visual outcomes.
The treatment of retinal capillary hemangioblastomas includes photocoagulation for smaller lesions, cryotherapy for larger and more peripheral lesions, and scleral buckling with cryotherapy or penetrating diathermy for extremely large lesions with extensive retinal detachment. External-beam and charged-particle radiotherapy have also been used. More recently, PDT has been used successfully to treat retinal capillary hemangioblastomas. Standard verteporfin dosing coupled with both standard and modified photodynamic protocols resulted in fibrosis of the hemangiomas with secondary retinal traction and improved visual acuity in recent studies.
Recent case reports have suggested the utility of targeted antiangiogenic therapy in the management of retinal capillary hemangioblastomas. The efficacy of antiangiogenic agents in the treatment of these vascular lesions is of compelling interest to von Hippel–Lindau patients, who have a lifelong risk of developing retinal angiomas. Both systemic and intravitreal VEGF inhibitors have been used. Reports to date suggest that the principal efficacy of VEGF inhibitors is in reducing macular edema. The impact on the actual size of the hemangiomas has been variable. Thus, the visual prognosis remains guarded for patients with large retinal lesions.