Ciliary Body and Choroidal Nevi
Nevi of the ciliary body are rare, mostly small, and often first identified in histologic examination of globes enucleated for other reasons. Choroidal nevi may occur in up to 8% of the population (Fig 17-4; see p. 310). Similar to iris nevi, in most cases they cause no symptoms and are recognized incidentally on routine ophthalmic examination. Ophthalmoscopically, the typical choroidal nevus appears as a flat or minimally elevated, pigmented (gray to brown) choroidal lesion with soft margins (see Fig 17-4A–E). Some nevi are amelanotic (see Fig 17-4F).
Choroidal nevi are often associated with overlying retinal pigment epithelium (RPE) disturbance and drusen (see Fig 17-4A, D). These features are characteristic of a long-standing, quiescent lesion. A minority develop atypical features such as localized serous retinal detachment over and around the nevus (see the section Melanoma of the Choroid and Ciliary Body), surface lipofuscin (see Fig 17-4E, F), or choroidal neovascular membranes. These atypical nevi may result in reduced vision, metamorphopsia, and visual field defects. Although these clinical features can be seen in the context of a benign lesion, they should also raise suspicion for malignant transformation, and careful follow-up for progression and lesion growth is indicated.
Table 17-1 Differential Diagnosis of Iris Melanoma
In the choroid, congenital ocular melanocytosis is similar in appearance to a diffuse nevus (see Fig 17-4G). This condition increases the lifetime risk for ciliary body and choroidal melanoma (1 in 400).
Findings on fluorescein angiography are not usually helpful for diagnosis; choroidal nevi may demonstrate either hypofluorescence or hyperfluorescence. Nevi are distinguished from choroidal melanomas and other pigmented fundus lesions by clinical evaluation and multimodal imaging, as described in the section Melanoma of the Choroid and Ciliary Body.
The management of choroidal nevi includes photographic documentation of all lesions; ultrasonographic measurement of lesions thicker than 1 mm; and lifelong, periodic reassessment for signs of growth or change consistent with transformation into choroidal melanoma (Fig 17-5). OCT can be helpful in excluding the presence of subclinical subretinal fluid.
Benign nevi may increase in diameter in the absence of malignant transformation. In a long-term study of choroidal nevi, nevi enlarged a median of 1 mm overall, but the median yearly rate of enlargement was less than 0.1 mm, and none of the enlarging nevi developed new orange pigment or subretinal fluid. Frequency of enlargement was reported to be 54% in patients younger than 40 years and 19% in patients older than 60 years. If rapid or more extensive enlargement is documented, especially in patients older than 40 years, malignant transformation should be suspected (Fig 17-6).
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Mashayekhi A, Siu S, Shields CL, Shields JA. Slow enlargement of choroidal nevi: a long-term follow-up study. Ophthalmology. 2011;118(2):382–388.
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Shields CL, Furuta M, Berman EL, et al. Choroidal nevus transformation into melanoma: analysis of 2514 consecutive cases. Arch Ophthalmol. 2009;127(8):981–987.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.