Generalized benign acanthosis nigricans.

with normal growth and developmental milestones, presented with asymptomatic generalized hyperpigmentation. It started spontaneously at the age of 2 years, around the neck and axilla, and spread insidiously to involve the other parts of body. The skin gradually became thickened and rugose. There was no history of drug intake, polyuria, polydypsia, loss of appetite, excess weight gain or loss. Cutaneous examination revealed generalized hyperpigmentation with thickening of skin, which was accentuated in the back and sides of the neck, axillae, groins, dorsal hands and flexural areas of knees and elbows. The characteristic velvety plaque with corrugated surface could be appreciated in the flexures (Fig.1). Mucous membranes, palms, soles, hair, and nails were unremarkable. Routine investigations, thyroid profile, insulin level, lipid profile, complete liver and renal function tests, and oral glucose tolerance test were within normal limits. Histopathological examination revealed marked hyperkeratosis, acanthosis and papillomatosis and was consistent with diagnosis of acanthosis nigricans. Epidermolytic hyperkeratosis was excluded on the basis of absence of bullous lesions and histopathological findings. Absence of mucosal and systemic involvement, and velvety texture of lesions in our patient were against the diagnoses of hemochromatosis and Addison’s disease.