Features
Choroidal melanoma is a primary cancer of the eye arising from the pigmented cells of the choroid. Choroidal melanomas are chemoresistant tumors and are life-threatening due to their metastatic potential. They are commonly unifocal and unilateral, and lesions appear as brown dome-shaped or mushroom-shaped masses arising from choroid, but may occasionally be amelanotic.
93.1.1 Common Symptoms
Small tumors are typically asymptomatic. At advanced stages, flashes and floaters, variable vision or visual field loss, and, rarely, pain secondary to neovascular glaucoma are possible.
93.1.2 Exam Findings
Choroidal melanomas are classified as small, medium, or large according to their largest basal diameter and height at the time of diagnosis (▶ Table 93.1). These are commonly unifocal and unilateral. Lesions appear as brown dome-shaped or mushroom-shaped masses arising from choroid, but may occasionally be amelanotic. Some have subretinal fluid or orange pigmentation (lipofuscin accumulation) overlying their surface (▶ Fig. 93.1). Choroidal melanomas may be associated with exudative retinal detachment, anterior segment neovascularization and secondary neovascular glaucoma, and episcleral sentinel vessels in the same quadrant when the tumor extends into the ciliary body.
Size | LBD | Height |
Small | 5–16 mm | 1.5–2.4 mm |
Medium | ≤ 16 mm | 2.5–10 mma |
Large | > 16 mm | > 10 mm |
Abbreviation: LBD, largest basal diameter. aChanged from 3.1 to 8 mm (November 1990). | ||
Fig. 93.1 Small choroidal melanoma. (a) Ultra-widefield fundus photograph of a small choroidal melanoma with overlying orange pigment. (b) Ultra-widefield fundus autofluorescence demonstrates both hyper-autofluorescence associated with areas of orange pigment and previous subretinal fluid and hypo-autofluorescence in the area of the nevus. (c,d) Optical coherence tomography demonstrates minimal subretinal fluid, lack of shaggy photoreceptors, outer retinal integrity disruption, choroidal elevation, and obliteration of the choroidal vasculature.
93.2 Key Diagnostic Tests and Findings
93.2.1 Optical Coherence Tomography
Optical coherence tomography (OCT) may demonstrate subretinal fluid overlying the lesion. Choroidal elevation is noted with obliteration of the overlying choroidal vessels and choriocapillaris. Alterations in retinal pigment epithelium structure may also be noted. Choroidal pathology may be best visualized with enhanced depth imaging or swept source optical coherence tomography.
93.2.2 Fluorescein Angiography or Ultra-Widefield Fluorescein Angiography
“Double-circulation” pattern (simultaneous fluorescence of retinal and tumor vessels) in venous phase.
93.2.3 Indocyanine Green Angiography
Hypofluorescence lesions (for smaller tumors) or presence of hyperfluorescent intrinsic choroidal vasculature (for larger tumors) in early phases (▶ Fig. 93.2), with variable leakage from the tumoral blood vessels in late phases.
Fig. 93.2 Large ciliochoroidal melanoma. (a) Ultra-widefield photograph demonstrating large ciliochoroidal melanoma obscuring view to the nasal retina. The ora serrata is visible at the apex of the tumor. (b) An external photograph documents its association with episcleral feeder vessels.
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