Choroidal Nevus with Retinal Invasion in 8 Cases

Abstract

Purpose: Choroidal nevus can cause overlying chronic retinal pigment epithelium (RPE) degenerative features, but frank retinal invasion is exquisitely rare. Procedures: This is a retrospective review of 8 cases of choroidal nevus with retinal invasion with evaluation of clinical and imaging features. Results: At the time of diagnosis of choroidal nevus with retinal invasion, mean patient age was 65 years. Mean tumor basal diameter was 7 mm, and mean thickness was 2.3 mm. Retinal invasion was ophthalmoscopically visible in all eyes. Related features included drusen (n = 4/8) and RPE fibrous metaplasia (n = 2/8). Overlying lipofuscin, subretinal fluid, RPE detachment, and retinal edema were absent. On B-scan ultrasonography, the lesion was dome-shaped (n = 7/7) and echo-dense (n = 6/7). Optical coherence tomography demonstrated outer retinal invasion (n = 8/8) with additional inner retinal invasion (n = 3/8). The tissue was hypoautofluorescent at the site of invasion (n = 6/7). Over a mean follow-up of 40 months, tumor enlargement was detected in 2 eyes and managed with observation (< 1 mm enlargement) or plaque radiotherapy (5 mm enlargement). Nevus hypoautofluorescence was correlated with nevus stability (p = 0.035). Conclusion: Retinal invasion of the choroidal nevus is rare. In this series of 8 cases, only 1 demonstrated transformation to melanoma over a mean interval of 40 months. Long-term monitoring of such lesions is warranted.

The MOLES System for Planning Management of Melanocytic Choroidal Tumors: Is It Safe?

“…Despite this, it is given a score of only 2 to simplify the scoring system on the assumption that tumors with this feature will have other indicators of malignancy, such as increased thickness. Occasionally, choroidal nevi can break through Bruch's membrane to invade the retina, [18] which is why this feature is given a score of only 1. (Figure 1 and Figure 2) Orange pigment has been shown by several studies to be helpful in differentiating choroidal melanomas from nevi [6][7][8][9][10][11].…”

Choroidal nevus with retinal invasion, clinical and imaging features

“…To our knowledge, there has only been one publication in the English literature describing choroidal nevus with retinal invasion. 5 Another publication found retinal invasion incidence to be 23–40% of enucleated eyes with choroidal melanoma. 6 This is compared to the less than <1% of choroidal nevi that exhibit retinal invasion.…”

“… 6 This is compared to the less than <1% of choroidal nevi that exhibit retinal invasion. 2 It is clear that choroidal nevi do not typically invade the outer or inner retina, 5 but it is important to distinguish them from choroidal melanoma when they do.…”

“…This darker area is typically brown and not black as found in RPE hyperplasia. 5 Other clinical features that may be present include associated fibrosis and drusen, and there is usually an absence of overlying orange pigment and SRF. 5 Additionally, the present case demonstrated a maximum thickness of 3.3mm and basal diameters of 10 mm × 10 mm, substantially greater than the mean thickness and basal diameter of choroidal nevus reported in most large series.…”

“…The mechanism of retinal invasion remains unknown, 9 but may be related to degenerative changes overlying the lesion, as described on the OCT, that leads to weakening of the Bruch's membrane and subsequently allowing nevus invasion of the retina. 5 …”