Choroidal Melanocytic Hamartoma

Abstract

We report on a case series that revealed flat, choroidal lesions on optical coherence tomography (OCT) and on enface MultiColor^® (MCI) imaging of the fundus but were not noticeable on clinical examination or conventional color fundus images. This observational study included 12 eyes from 11 patients who had distinct, orange-colored lesions on MCI. Retinal imaging was conducted using conventional color fundus photography and OCT. On the color fundus images and the blue and green reflectance channels of MCI, each of the lesions was difficult to distinguish. On the infrared channel, the lesion was identified as bright white in color and bright orange on the multicolor image. The lesion was identified on OCT as a flat, homogeneous hyperreflective lesion involving the choroid, with an intact overlying retinal pigment epithelium and retinal layers. A comparison of the clinical and imaging features with other known entities led to the conclusion that the lesion was a distinct clinical entity. The presence of melanin in the lesion was confirmed based on the retinal imaging findings and the light absorption properties of melanin. As a result, the lesion was named as 'choroidal melanocytic hamartoma'. A longer follow-up is required to confirm the benign nature of this clinical entity.

Keywords: choroid; hamartoma; melanin; multimodal imaging.

Figure 1

Multimodal imaging in a patient showing isolated choroidal melanocytic hamartoma in the right eye. (A) Conventional color fundus image of the posterior pole obtained using the Topcon TRC 50 Dx fundus camera. The color fundus image looks normal and does not identify any significant pathology. (B) The 55° blue wavelength autofluorescence image appears normal. (C–F) A bright orange colored lesion is noted along the superotemporal vessel on the 55° multicolor image (white arrow) and is seen as a bright white hyperreflective lesion on the infrared reflectance channel (white arrow). The lesion is not visible on the short wavelength green and blue reflectance channels. (G) Enhanced depth imaging optical coherence tomography scan passing through the fovea and lesion showed a normal foveal contour and increased reflectivity in the choroid with poor visibility of the underlying structure at the area of the lesion (white arrow).

Figure 2

Multimodal imaging in a patient with neurofibromatosis type 2 showing multiple isolated choroidal melanocytic hamartomas in the left eye. (A) Slit-lamp photograph with oblique illumination shows the Lisch nodules on the iris surface. (B) The 50° conventional color fundus photograph of the left eye looks normal and does not identify any pathological lesions. (C–F) The 30° multicolor image shows multiple choroidal melanocytic hamartomas spread across the posterior pole as bright orange-colored lesions (white arrows). On the high wavelength infrared reflectance channel, the lesions appear as white hyperreflective lesions (white arrows). The lesions are not visible on the short wavelength green and blue reflectance channels. (G) Enhanced depth imaging optical coherence tomography scan passing through one of the lesions shows increased reflectivity in the choroid with poor visibility of underlying structure at the area of the lesion (white arrow).

Figure 3

Flow chart depicting the clinical and imaging findings of different differential diagnosis.