Nevus of Ota is a hamartoma of dermal melanocytes presenting as blue hyperpigmented patches on the face usually within the distribution of ophthalmic and maxillary branches of the trigeminal nerve. A case of giant nevus of Ota involving all three branches of the trigeminal nerve is presented.
An 18-year-old girl presented with skin hyperpigmentation over the left side of the face since childhood. External examination revealed bluish hyperpigmented patch involving the forehead, periorbital area, temple, cheek and mandibular area [Fig. 1]. Examination of the left eye showed conjunctival melanocytosis, anterior and intercalary staphyloma, leucomatous corneal opacity and pseudoproptosis [Fig. 2]. The right eye was essentially normal. Visual acuity was nil perception of light in the left eye and 20/20 in the right eye. Left eye ultrasound ruled out intraocular mass and showed optic nerve head cupping; the axial length was 31 mm [Fig. 3]. Magnetic resonance imaging of brain done elsewhere (images not available) was reported normal. She underwent enucleation of the left eye. Histopathological examination of enucleated eye revealed melanocytic proliferation in the conjunctiva, iris, cilary body, choroid and sclera [Fig. 4].
Nevus of Ota usually appears at birth and has a female preponderance (4.8:1). It may be associated with nevus of Ito, ocular melanoma (1 in 400) and glaucoma (10.3%). Hence, the need for detailed ophthalmic and systemic examination. Histologically it is classified into five types, which are superficial, superficial dominant, diffuse, deep dominant, and deep. The more superficial lesions tend to be located on the cheeks while deeper lesions occur on periorbital areas, temple, and forehead. This classification bears significance in making a therapeutic prognosis of the disease. A lifelong follow-up with dermatologist and ophthalmologist is required given the increased incidence of malignant melanoma.
Dr. Jyotirmay Biswas for his help with histopathological slides.
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Conflicts of Interest: None declared.