An update on ophthalmological perspectives in oculodermal melanocytosis (Nevus of Ota)

Prevalence of glaucoma and characteristics of ocular manifestations in patients with Naevus of Ota

AIMS

This cross-sectional study aimed to determine the prevalence of glaucoma and associated ocular characteristics in Thai patients with Naevus of Ota, comparing those with ocular melanocytosis or oculodermal melanocytosis to those exhibiting only skin hyperpigmentation.

METHODS

Patients who were diagnosed with Naevus of Ota at Siriraj Hospital, Thailand, underwent a comprehensive ophthalmic assessment by a glaucoma specialist. Those unable to cooperate in an outpatient setting were examined under general anaesthesia. The assessments comprised visual acuity, intraocular pressure (IOP), anterior segment findings, gonioscopy, corneal diameter (in patients aged <3 years) and fundus examination. Visual field and optical coherence tomography tests were performed as indicated.

RESULTS

A total of 163 patients (184 eyes) were examined, including 115 eyes with ocular melanocytosis or oculodermal melanocytosis. The mean age at examination was 15.0±15.6 years. Open-angle glaucoma was identified in 2 eyes (1.1%), ocular hypertension in 6 eyes (3.3%) and glaucoma suspicion in 16 eyes (8.7%). Among those with ocular melanocytosis or oculodermal melanocytosis, ocular hypertension and glaucoma suspicion were more common (4.3% and 12.2%, respectively) than in those with only skin hyperpigmentation (1.4% and 2.9%, respectively).

CONCLUSION

Although the prevalence of glaucoma in Naevus of Ota is low, patients with ocular melanocytosis or oculodermal melanocytosis are at greater risk of ocular hypertension and suspected glaucoma than are those with skin-only hyperpigmentation. Targeted screening, particularly in younger individuals and those requiring examination under general anaesthesia, should be considered. The main limitation of the study is its cross-sectional design, offering only a one-time view of a prolonged clinical progression. Moreover, the use of anaesthetic inhalation could have resulted in lower IOP readings during general anaesthesia.

TRIAL REGISTRATION NUMBER

TCTR20210223004.

Primary orbital melanoma in a patient with nevus of Ota

Primary orbitary melanoma is a very rare malignancy which grows adjacent to melanocyte-rich areas. This is the case of a 48 years-old woman with oculodermal melanocytosis who develops a primary orbital melanoma. After the first approach with exeresis and adjuvant radiotherapy and a subsequent management with orbital exenteration and adjuvant immunotherapy; the patient has reached a remission period of 12 months so far. With this case the aims are to emphasize the severe complications potentially associated to the oculodermal melanocytosis and to demonstrate the need of treating complex patients through multidisciplinary teams.

Oculodermal melanocytosis in Asian Indian patients: Prevalence, clinical presentation, and association with choroidal melanoma

OBJECTIVE

To study the prevalence, clinical presentation, treatment, and follow-up of ocular (dermal) melanocytosis (ODM) and its association with choroidal melanoma (CM) in Asian Indian patients.

METHODS

This was a retrospective case series of patients with ODM conducted in a quaternary eye care center.

RESULTS

Of the total 1.48 million patients during the study period, we identified 213 patients with ODM with a prevalence rate of 0.014%. Median age at presentation was 13 years (range 0-76 years). Unilateral presentation of ODM was noted in 87% cases. ODM involved the sclera in 100% cases, the iris in 23%, the choroid in 20%, the eyelid in 29%, and V1 and V2 dermatomes in 53% cases. Nineteen patients (9%) were found to have CM, with 1.3 times increased risk of CM compared to the Caucasian population. The most common tumor location was in the inferior quadrant (n = 8, 44%). The mean tumor thickness was 8.3 ± 2.8 mm with a mean basal diameter of 14.0 ± 4.3 mm. Primary treatment of CM included plaque brachytherapy (n = 6), enucleation (n = 9), and few patients refused for treatment (n = 3). During a mean follow-up period of 21 months, one patient died because of lung metastasis.

CONCLUSION

Although rare, choroidal melanoma does occur in the presence of ODM with an increased risk in Asian Indians compared to the Caucasian population. Patients with ODM should be examined periodically for early detection of CM.

Symptomatic Vitreous Opacities: Exploring the Mismatch between Clinical Observation of Vitreous Alterations and Self-Reported Symptoms

Objectives: To assess the mismatch between the clinical observation of vitreous alterations and self-reported symptoms in young patients complaining of symptomatic vitreous opacities (SVO). Methods: The ophthalmic medical records of young patients presenting primarily with SVO were retrospectively evaluated. Symptoms severity was assessed using a questionnaire. The status of the vitreous body was examined with indirect ophthalmoscopy at the slit-lamp and classified according to an ad hoc severity scale. Results: Sixty eyes of thirty otherwise healthy patients (median age: 32.5 (IQR: 29.0-37.0) years old) complaining of SVO (median duration: 38 months; interquartile range: 18-84 months) were enrolled. SVO was rated as severe by 50% of participants, affecting all the activities explored in the questionnaire. Twenty-three patients (76.6%) reported SVO-related depression and/or anxiety, for which eleven patients (36.6%) were or had been using medication. Fifty-eight eyes (96.6%) showed no evidence of (or minimal) vitreous opacity, while two eyes (3.3%) were found to have significant vitreous opacity. No significant inter-gender differences (p > 0.05) and no significant differences (p > 0.05) were found between the severity of vitreous opacity and patients' reported symptoms nor with their psychological status and medication use. Conclusions: Severe discomfort related to the perception of vitreous floaters exists in young patients whose vitreous gel examination is unremarkable or shows only minor alterations. We believe this discrepancy can be explained by optical anisotropy; significant forward-scattering of light, which results in floater symptoms; and reduced back reflection, which limits the clinical observation.

Concurrent Occurrence of Trichilemmal Cyst and Nevus of Ota: Case Series

Nevus of Ota or congenital oculodermal melanosis (ODM) is characterized by brown or blue/gray asymptomatic brown or blue/gray flat lesions of the skin, mucosae, episcleral/sclera, and uvea, which are located near the trigeminal nerve's ophthalmic and mandibular branches. The main ophthalmic complications are glaucoma and predisposition to uveal melanoma. "trichilemmal cyst" is also known as "wen" "pilar cyst" or " isthmus catagen cyst". It occurs in the scalp and mimics sebaceous cysts clinically. The swelling appears smooth in outline and is filled with cytokeratin. An unusual case of a 32-year-old male with both trichilemmal cyst and nevus of Ota, a 27-year-old female, and a 47-year-old male with nevus of Ota is discussed here.

Disrupting Hedgehog signaling in melanocytes by SUFU knockout leads to ocular melanocytosis and anterior segment malformation

Hedgehog (Hh) signaling is well known for its crucial role during development, but its specific role in individual cell lineages is less well characterized. Here, we disrupted Hh signaling specifically in melanocytes by using Cre-mediated cell-type-specific knockout of the Hh regulator suppressor of fused (Sufu). Interestingly, corresponding mice were fully pigmented and showed no developmental alterations in melanocyte numbers or distribution in skin and hair follicles. However, there were ectopic melanoblasts visible in the anterior chamber of the eye that eventually displayed severe malformation. Choroidal melanocytes remained unaltered. Surprisingly, the abnormal accumulation of anterior uveal melanoblasts was not the result of increased cell proliferation but of increased migration to ectopic locations such as the cornea. In melanoblasts in vitro, Sufu knockdown replicated the increase in cell migration without affecting proliferation and was mediated by an increased level of phosphorylated-ERK brought about by a reduction in the levels of the repressor form of GLI3. These results highlight the developmental divergence of distinct melanocyte subpopulations and may shed light on the pathogenesis of human ocular melanocytosis.