If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Correspondence to: Patricia Hrynchak, OD, School of Optometry and Vision Science, University of Waterloo, 200 University Avenue W. Waterloo, Ontario, N2L 3G1;
Ocular melanocytosis is a congenital hyperplasia of the melanocytes in the ocular tissues: episclera, iris, ciliary body, and choroid. It is usually unilateral but can be bilateral. It can affect the surrounding eyelids, as in oculodermal melanocytosis, or be isolated to the choroid, which is referred to as isolated choroidal melanocytosis. Isolated choroidal melanocytosis is an uncommon condition that has been reported unilaterally in a number of cases,
We present a case of bilateral isolated choroidal melanocytosis in which there is isoautofluorescence in the affected areas, suggesting an overlying healthy retinal pigment epithelium (RPE).
Case Report
A 34-year-old male from Greece presented for a full eye examination. His ocular history included blunt trauma to the right eye 1 year previously. He was not assessed for that injury but did not report any sequelae. His medical history was positive for hearing loss secondary to tympanic membrane damage from otitis as a child. He denied any other health problems and was not taking any medication.
Presenting best-corrected visual acuity was −0.15 logMAR OU. There was no pigment noted on the eyelids, iris, episclera, or sclera of either eye. Intraocular pressures were 12 mm Hg at 2:32 pm in each eye. Dilated fundus examination showed healthy optic nerves with a vertical cup-to-disc ratio of 0.30 in the right eye and 0.45 in the left eye. Examination of the retina revealed a large area of flat, confluent choroidal hyperpigmentation with feathered boarders in each eye. It included the subfoveal area and extended to the ora in both eyes. In the right eye it extended 7 clock hours, and in the left eye it extended 12 clock hours (Fig. 1). Optical coherence tomography (OCT) images (Fig. 2) were captured for each eye and are shown for the left eye. The OCT (Heidelberg OCT Spectralis) showed normal retinal structure over the pigmented areas. Fundus autofluorescence imaging also done with the Spectralis revealed isoautoflourescence over the pigmented areas (Fig. 3).
Fig. 1Photographs of the choroidal pigmentation in the right (A) and left (B) eye, respectively.
Fig. 2Optical coherence tomography showing normal structure of the inner and outer retinal layers over the hyperpigmentation of the choroid in the left eye.
The differential diagnosis for hyperpigmentation in the choroid includes large nevi, bilateral diffuse uveal melanocytic proliferation syndrome, diffuse choroidal melanoma, and isolated choroidal melanocytosis.
Most are small (1.5–5 mm in diameter), flat, and located posterior to the equator. They have minimal thickness and an irregular border and often have overlying drusen.
Bilateral diffuse uveal melanocytic proliferation syndrome is rare paraneoplastic syndrome that is associated with an occult or previously diagnosed systemic cancer. There is a proliferation of melanocytes in the outer choroid that are unrelated to the primary nonocular tumour by histopathology. The presentation includes decreased visual acuity, small pigment patches with moderate thickening, and focal serous detachment. It shows hyper- and hypoautofluorescence over the affected areas.
Diffuse choroidal melanoma is an unusual variant of choroidal melanoma. It has a horizontal, flat growth pattern with a thickness that is approximately ≤20% of the basal diameter. It can easily be misdiagnosed because of the relatively thin appearance, but suspicious features include orange pigment that produces bright hyperautofluorescence, subretinal fluid, location near the optic nerve, thickness greater than 2 mm, poorly defined margins, and visual symptoms.
None of the these presentations were consistent with our case, which left isolated bilateral choroidal melanocytosis as the most likely working diagnosis.
Isolated choroidal melanocytosis has been considered a subtype of ocular melanocytosis.
It generally presents unilaterally and features choroidal vessel sparing and a lack of overlying drusenoid degeneration, lipofuscin, and/or serous detachment. These findings indicate that the pigment is isolated to Haller’s layer and there is no RPE disruption.
One hypothesis is that the hyperpigmented patches could be caused by increased melanin production in the normal population of melanocytes. If this is true, it could be called melanosis rather than melanocytosis.
in a series of unilateral cases, reported an increased ratio between the perivascular stromal thickness and the entire choroidal thickness in affected eyes, suggesting that the increase is caused by increased cellularity. Definitive biopsy studies are not indicated because of the benign nature of the condition.
In unilateral cases comparing the affected and the unaffected eye, OCT showed an increased choroidal thickness (51%) in the affected eye, specifically of the perivascular interstitial tissue enwrapping the vessels.
We were unable to measure choroidal thickness in our patient. We were, however, able to attain fundus autofluorescence imaging, which did not reveal any hyper- or hypoautofluorescence. This indicated no accumulation of lipofuscin or disruption of the RPE.
In Augsberger’s series, unilateral lesions did not enlarge during follow-up of 6 months to 13 years.
Unlike eyes with ocular melanocytosis, in unilateral isolated cases the lifetime risk of developing uveal melanoma may only be slightly higher than that in the general population.
In bilateral cases it may be similar; however, annual monitoring is recommended. Fundus autofluorescence may be a useful tool to use in the differential diagnosis of this presentation.
Disclosure
The authors have no proprietary or commercial interest in any materials discussed in this article.
References
Augsburger J.J.
Trichopoulos N.
Corrêa Z.M.
Hershberger V.
Isolated choroidal melanocytosis: a distinct clinical entity?.
in: Duane’s Foundations of Clinical Ophthalmology, volume 3, chapter 20. Tasman W, ed.Lippincott Williams and Wilkins,
Philadelphia, PA2004 (on CD-ROM)
30815-3&id=gr1.jpg){kind=link}
30815-3&id=gr2.jpg){kind=link}
30815-3&id=gr3.jpg){kind=link}