An 18-year-old woman was seen in the clinic with complaints of a bizarre hypopigmentation of her skin which her mother said had been present from birth and had been asymptomatic, constant, and permanent. She also complained of a rough eruption which had developed at one year of age and had progressed slightly in size over the years. It was first noticed in the left axilla, groin, parasternal area and posteriorly on the neck and was restricted to the left side of the body. It became inflamed and pruritic, was asymptomatic at times, but never cleared although the patient felt some of the lesion had sloughed off. There were no associated systemic symptoms, no history of seizures, and her psychomotor development was normal. On examination, the main findings were mucocutaneous; she had hypopigmented bands, whorls, and streaks following Blaschko's lines, the lesions affected the front and the back of her trunk bilaterally, with the arms and thighs also involved. Her face was spared (Fig. la and b). There was no evidence of atrophy or scarring in the hypopigmented lesions. The patient also had linear verrucous lesions in left armpit, left hand (dorsal surface), left groin, left parasternal region (Fig. 2) and posteriorly on the neck (Fig. lb). The lesions in some areas were fragile and there was evidence of shedding in some places, leaving hypopigmented lesions; no vesicles were seen. Her hair, nails, and teeth were normal, as were the musculo-skeletal, ocular, and central nervous system. A diagnosis of nevus depigmentosus with inflammatory linear epidermal nevus to rule out incontinentia pigmenti was made. Skin biopsies were taken from the whorled, hypopigmented, and verrucous patches. The biopsy result of the hypopigmented patch showed an essentially normal looking epidermis and dermis; there was no melanin incontinence. The verrucous patch showed hyperkeratosis, psoriasiform hyperplasia of the epidermis with regular alternation of parakeratotic areas with hypergranulosis and orthokeratosis with a reduction in the granular layer.
