Imaging a choroidal nevus

A mid-50s female was sent for imaging of a choroidal nevus that had been followed clinically for several years without observation of changes. There was no suspicion of growth or significant elevation. The purpose of the imaging studies was to establish digital baseline characteristics and to add additional documentation. The lesion was not considered high risk clinically based on the To Find Small Ocular Melanoma (TFSOM) criteria.^1,2

The ocular, medical, and family histories of the patient were non-contributory. Visual acuity was correctable to 20/20 in each eye. The patient was a satisfied monovision contact lens wearer.

Figure 1

Figure 1 shows the widefield image of the patient’s right eye. Note that there is a lesion that appears to differ in color from the surrounding retina. Based on the optic disc, the nevus appears to be about a 1 DD in size. Using monocular cues, a vessel changes course over the top of the lesion, suggesting minimal elevation.

All of the OCT scans are of high signal strength. Figure 2 is the OCT of the macula, which is grossly normal. The elevation in the lower right portion of the topographic segments represents the slight elevation of the nevus but without loss of integrity of the retinal pigment epithelium (RPE).

Figure 3

A horizontal 5-line raster HD image was obtained through the nevus. Figure 3 shows the elevation from the lesion as well as irregularity of the RPE overlying it and the thickened retina above. Drusen on the surface of a nevus indicates a long-standing lesion and suggests benignity. A different segment (vertically oriented) is shown in Figure 4, demonstrating a small amount of fluid under a portion of the RPE. This segment was used to measure the apical height (thickness) of the nevus. The threshold for suspicion among nevi is generally 2 mm. So, this lesion is well under that dimension, which supports the benign nature of it. Another horizontal HD section helps to visualize the three-dimensional shape of the lesion. (Figure 5).

Figure 4

Figure 5

The interested reader is referred to a recent description of the OCT characteristics of choroidal nevi.³ This case is consistent with published findings.ODT

References

1. Shields CL. The hunt for the secrets of uveal melanoma. Clin Experiment Ophthalmol. 2008 Apr;36(3):277-80.

2. Shields CL, Furuta M, Berman EL, Zahler JD, et al. Choroidal nevus transformation into melanoma: analysis of 2514 consecutive cases. Arch Ophthalmol. 2009 Aug;127(8):981-7.

3. Say EA, Shah SU, Ferenczy S, Shields CL. Optical coherence tomography of retinal and choroidal tumors. J Ophthalmol. 2012;2012:385058.