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Retinal capillary haemangiomas are benign vascular tumours composed of primitive blood vessels in a loose connective tissue stroma. These vessels leak fluid, which may lead to the formation of exudates, haemorrhage and retinal detachment.
At least a quarter of patients with retinal capillary haemangiomas develop one or more associated intracranial or systemic lesions, in an autosomal dominantly inherited condition known as von Hippel Lindau syndrome (VHLS).
Symptoms
The most common pathways to the diagnosis are:
- Asymptomatic tumours detected at routine examination, usually in the second or third decade of life
- Routine screening of members of families carrying the VHLS mutation
- Symptomatic lesions - most commonly visual impairment from complications of retinal capillary haemangiomas.
Signs
Retinal capillary haemangiomas initially appear as small red dots, usually in the mid-peripheral fundus. Over several years they enlarge to become elevated, yellow-red tumours with a tortuous, dilated feeder artery and draining vein. These feeder vessels are much shorter and less prominent with peripapillary tumours. Rarely, tumours extend outward (that is, exophytic capillary haemangioma), rendering them less visible at fundoscopy.
Leakage of fluid, lipids and other blood components from larger tumours often results in the accumulation of hard exudates and subretinal fluid in a ring around the lesion. Exudates and oedema may also form at the macula, presumably because the retinal pigment epithelial pump is most active in this location, and therefore concentrates extracellular debris.
Other complications of advanced tumours include epiretinal membrane formation, retinal detachment (serous, exudative or tractional) and vitreous haemorrhage. Rarely, glaucoma and phthisis bulbi (a shrunken, scarred, opaque and usually blind eye) have been reported in advanced, severe disease.
Prevalence
Rare.
Significance
Retinal capillary haemangiomas are the most common, and often initial, manifestation of VHLS.
Differential diagnosis
Coats' disease (Retinal telangiectasia), Retinal arterial macroaneurysm, Retinoblastoma.
See also
Von Hippel Lindau syndrome, Retinal detachment classification.
Management
The prognosis for vision varies with the location, size and complications of the lesion. Treatment is complex. The potential benefits (such as resolution of exudates and oedema, prevention of retinal detachment and preservation of vision) must be weighed against possible complications (such as vitreous haemorrhage, progressive exudation and retinal detachment).
Additional investigations
Fluorescein angiography is performed prior to treatment. The tumour fills rapidly with dye, and leaks during the late phase.
Systemic evaluation for possible associated capillary haemangiomas is commonly considered in the presence of multiple retinal capillary haemangiomas, or single haemangiomas in patients with a family history of VHLS. This may include magnetic resonance imaging (MRI), computed tomography (CT) scans, screening blood tests and urinalysis.
Genetics
Genetic assessment for the VHLS mutation may be advisable.
Laser surgery
When progression in size or exudation is detected, laser photocoagulation, photodynamic therapy and/or cryotherapy is performed. Should these treatments fail, radiotherapy or local excision may be considered. Lesions within 5mm of the fovea require specialised assessment.
Incisional surgery
Larger tumours may be treated with diathermy, radiotherapy or surgical resection. Vitreoretinal surgery may be required for persistent vitreous haemorrhage or epiretinal membranes. Visual improvement is unlikely in cases complicated by total retinal detachment or extensive fibrosis.
Review
Small, peripheral lesions may remain stable for many years, and are observed at regular intervals. Ongoing systemic evaluations may also be recommended.