Ocular findings in a case of periorbital giant congenital melanocytic nevus.

Giant congenital melanocytic nevus (GCMN) is a large melanocytic nevus that rarely occurs in the periorbital region. Various systemic, as well as ophthalmic associations, have been reported with GCMN. However, there is only one case report describing ophthalmic findings in periorbital GCMN. We describe the ocular findings in a case of periorbital GCMN.

Introduction

Giant congenital melanocytic nevus (GCMN) is usually defined as a melanocytic lesion present at birth that will reach a diameter ≥20 cm in adulthood.[1] Its incidence is estimated in <1:20,000 newborns. Periorbital region is a rare site of occurrence of congenital hairy melanocytic nevus, especially the giant form. We describe the ocular findings in a 6 years old girl, with a periorbital GCMN.

Case Report

A 6-year-old girl presented with redness and watering associated with a decrease in vision in the left eye for 1 week. There was no history of preceding trauma or fever and no history of taking any treatment. She had a giant pigmented hairy nevus involving both the lids on the left side and the nose, present since birth and gradually increased in size with age [Figure 1]. Her best-corrected visual acuity in the right eye was 20/20, while in the left eye was 20/100.

Figure 1

Clinical photograph of the patient showing giant hairy congenital melanocytic nevus involving the nose and the left upper and lower lids

On ocular examination, she was orthophoric, and the ocular movements were full and free. The right eye was within normal limits. The left eye showed diffuse conjunctival congestion suggestive of viral conjunctivitis and conjunctival melanosis in the superonasal quadrant [Figure 2]. There was also a paracentral macular corneal opacity, 0.5 cm in diameter with superior pannus; and iris melanosis between 11 and 12 o’clock [Figure 3]. There was no evidence of any cells or flare in the anterior chamber. The left eye optic disc was hyperemic with dilated and tortuous vessels whereas the rest of the retina was normal [Figure 4]. The intraocular pressure measured by Goldmann applanation tonometer was 14 mm of mercury in both eyes. Hertel's exophthalmometry was 16 mm in both eyes at the bar reading of 92 mm.

Figure 2

Slit lamp photograph of the patient showing conjunctival congestion and conjunctival melanosis in the supero-nasal quadrant

Figure 3

Slit lamp photograph of the patient showing paracentral macular corneal opacity (red arrow), superior pannus (yellow arrow) and iris melanosis (white arrow)

Figure 4

Fundus photograph of the left eye showing optic disc hyperemia and dilated and tortuous vessels

The patient was started on topical antibiotic and lubricants, and she improved within a week. Retinoscopy under 2% homatropine revealed no refractive error in the right eye, whereas the left eye had an astigmatism of − 2 DC at 180°. However, the left eye vision did not improve with refraction, indicating anisometropic amblyopia. Magnetic resonance imaging (MRI) scan of brain and orbits was done and was within the normal limits. The patient was referred to the plastic surgery department for further management.

Comment

Despite its rarity, GCMN is important because it may be associated with severe complications such as malignant melanoma, affect the central nervous system (neurocutaneous melanosis), and have major psychosocial impact on the patient due to its unsightly appearance, especially if it is present on the face. Other rare systemic associations reported are diffuse lipomatosis, hypertrophy of cranial bones, atrophy of limbs, skeletal asymmetries, scoliosis, urinary tract anomalies, capillary vascular malformations, cafe-au-lait spots, ectopic mongolian spots, fibroepithelial polyps and CNS malformations like arachnoid cysts, choroid plexus papilloma, cerebellar astrocytoma, type I Arnold-Chiari and Dandy-Walker malformation.[1] Ophthalmic findings reported in association with GCMN include ectopic lacrimal gland, intraocular choristoma, anterior staphyloma, ankyloblepharon and iris melanosis.[234]

Giant congenital melanocytic nevus is mostly found on the trunk, followed by the limbs and the head. Multiple smaller congenital nevi called satellite lesions may also be seen in the vicinity of the main nevus.[1]

Periorbital region is an uncommon site for the occurrence of congenital hairy melanocytic nevus, especially involving both lids (called divided nevus), with roughly 40 cases reported in the literature.[5] The giant form is the rarest, and there are very few cases of periorbital giant congenital hairy melanocytic nevus reported in the literature.[36] Only one of them had associated ocular findings like ocular choristoma and anterior staphyloma.[3] Our patient had conjunctival and iris melanosis as the ocular findings in periorbital GCMN.

Since, the MRI of brain and orbits was normal, the left fundus findings remain unexplained. It might be due to occult melanocytic deposits in the lepto-meninges (neurocutaneous melanosis) or left optic nerve sheath that are known to be missed on MRI, and can only be confirmed on autopsy.