Choroidal and Retinal Tumors in Adults: Choroidal Melanocytic Lesions

CHOROIDAL NEVUS Choroidal nevus (Figure 1), the most common primary intraocular tumor,1 is a benign tumor that arises from melanocytic cells derived from the neural crest. Choroidal nevi are more common in white people, with 4% of the population having at least one.1 Malignant transformation into melanoma is possible; therefore, choroidal nevi should be monitored even though the rate is 1 in 4,000.2 As noted below, certain risk factors are associated with a higher risk of transformation. Clinical features. Most choroidal nevi are congenital, but they usually do not become pigmented and clinically detectable until after childhood. They can be pigmented, amelanotic, or partially pigmented. Although the majority of choroidal nevi are asymptomatic, approximately 11%, either subfoveal or located near the fovea, become symptomatic later due to subretinal fluid and choroidal neovascularization.3 Diagnostic approaches. There is little difference in the diagnostic and prognostic values of fluorescein angiography (FA) or indocyanine green (ICG) angiography. Choroidal nevi can vary from hypoto hyperfluorescence. Most benign choroidal nevi do not have prominent intralesional blood vessels, whereas most choroidal melanomas do. Fundus autofluorescence (FAF) is useful because it detects orange pigment, one of the most relevant risk factors for a growing tumor.4 Ultrasound can be used for baseline thickness measurements and to determine acoustic hollowness, a prognostic factor that is associated with the nevus possibly being malignant. Differential diagnoses. The differential diagnoses of choroidal nevus include choroidal melanoma, metastatic carcinoma, choroidal hemangioma, choroidal osteoma, schwannoma, subretinal or suprachoroidal hematoma, congenital hypertrophy of the retinal pigment epithelial (RPE) cells, and reactive hyperplasia of the RPE. Management. Asymptomatic choroidal nevus does not require treatment. In symptomatic cases with choroidal neovascularization or subretinal fluid, laser photocoagulation, photodynamic therapy, or transpupillary thermotherapy can be used; however, Choroidal and Retinal Tumors in Adults: Choroidal Melanocytic Lesions