Progressive retinal invasion and vitreous seeding from optic disc melanocytoma

Two Cases of Giant Melanocytoma (Hyperpigmented Magnocellular Nevus)

Melanocytoma or hyperpigmented magnocellular nevus is a variant of melanocytic nevus that is most commonly seen in the optic nerve, but has also been reported to occur in the iris, ciliary body, choroid, sclera, and conjunctiva. We present two cases of giant uveal melanocytoma with histopathology. The first case occurred in a 10-year-old girl who presented with decreased vision in the right eye and a mushroom-shaped pigmented choroidal lesion measuring 15.5 mm in apical height. The lesion was abutting the lens but not causing a cataract. This was diagnosed as a choroidal melanocytoma on open scleral window biopsy. The second case was in a 68-year-old lady, referred for a left nasal pigmented choroidal lesion measuring 8 mm in apical height and having a mushroom configuration. The lesion grew to 8.6 mm in height and was complicated by a vitreous hemorrhage and rhegmatogenous retinal detachment and was treated with iodine-125 plaque brachytherapy. Subsequently, the treated eye became a painful phthisical eye and was enucleated. Histopathology confirmed melanocytoma with extrascleral extension but without malignant transformation. Features of melanocytoma and other very large cases reported in the literature are discussed.

Clinical and Spectral-Domain Optical Coherence Tomography Appearance of Optic Disc Melanocytoma: A New Classification and Differentiation from Pigmented Choroidal Lesions

AIMS

The aim of this paper was to compare the features of both the classic, darkly pigmented and the atypical, more lightly pigmented optic disc melanocytoma with those of pigmented choroidal lesions.

METHODS

We analyzed the spectral-domain optical coherence tomography (SD-OCT) features of 9 eyes with optic disc melanocytoma and compared them with those of choroidal melanoma and nevus.

RESULTS AND CONCLUSION

We identified 2 categories of SD-OCT findings in optic disc melanocytoma: (a) type 1, the typical, prominent, hyperpigmented lesion with SD-OCT findings of a hyperreflective, disorganized overlying retina and a posterior hyporeflective shadow, and (b) the less common, atypical, minimally pigmented type 2 lesion overlaid by a relatively well-organized retina that lacks a posterior hyporeflective shadow. Choroidal lesions were characterized by tumor confined beneath the clearly visible hyperreflective line of the photoreceptor and retinal pigment epithelium, with minimal disorganization of the overlying retina.

Infrared autofluorescence, short-wave autofluorescence and spectral-domain optical coherence tomography of optic disk melanocytomas

AIM

To investigate the findings of infrared fundus autofluorescence (IR-AF) and spectral-domain optical coherence tomography (SD-OCT) in eyes with optic disc melanocytoma (ODM).

METHODS

IR-AF findings and those of other ophthalmologic imaging examinations, including short-wave autofluorescence (SW-AF), fluorescein angiography (FA), fundus color photography, and SD-OCT of 8 eyes of 8 consecutive cases with ODM were assessed.

RESULTS

The ODMs in all cases (100%) presented similar IR-AF, SW-AF, and FA findings. On IR-AF images, ODMs showed outstanding hyper-AF with well-defined outline. On SW-AF images, the area of ODMs presented as hypo-AF. FA images revealed the leaking retinal telangiectasia on the surface of the ODMs. On SD-OCT images in 8 cases (100%), the ODMs were sloped with highly reflective surface, which were disorganized retina and optic nerve layers. In 7 cases (87.5%), peripapillary choroids were involved. The melanocytomas of 8 cases (100%) presented as optically empty spaces. Vitreous seeds were found in one case (12.5%).

CONCLUSION

IR-AF imaging may provide a new modality to evaluate the pathologic features of ODMs, and together with SW-AF imaging, offers a new tool to study biological characteristics associated with ODMs. SD-OCT is a valuable tool in delimitating the tumor extension and providing morphological information about the adjacent retinal tissue.

Pigment dispersion syndrome associated with optic nerve melanocytoma

CASE REPORT

A 60-year old patient was referred for cataract surgery. The examination showed retrokeratic pigment in the left eye, which had an intraocular pressure of 24 mm Hg. The funduscopy showed a brown lesion on the left optic disk, with adjacent vitreous seeding of pigment. The patient was thus diagnosed with secondary pigment dispersion syndrome due to optic disk melanocytoma.

DISCUSSION

Although melanocytoma is most commonly a benign, stationary tumor, it may present with major complications leading to significant visual loss. A patient with melanocytoma of the optic disk should be examined periodically.