Samuel William Becker first described this nevus in 1848. It has also been referred to as “Nevoid Melanosis,” “Becker’s Melanosis,” and “Pigmented Hairy Epidermal Nevus.” It is a late-onset epidermal nevus that usually is not present at birth but develops just before puberty and almost all patients are males.
It presents as a hyperpigmented, hypertrichotic (hypertrichosis) unilateral patch on the upper trunk or proximal upper extremity. Acneiform lesions may be present. The lesion is often asymptomatic, and after puberty it darkens and may become quite hairy, a condition called hypertrichosis. It is associated with a smooth muscle hamartoma histologically. The pathogenesis may be related to increased expression of androgen receptors within lesional skin. In Andrews’ Disease of the Skin they report some additional rare associations:
- Connective tissue nevus
- Inflammatory linear verrucous epidermal nevus
- Basal cell carcinoma
- Phakommatosis pigmentovascularis
- Becker nevus syndrome–abnormalities of underlying tissues involved with the same embryonic cell type–the ectoderm, a type of epidermal nevus syndrome
TREATMENT: Usually not necessary, but many patients are bothered by the hairy appearance. Ablative 10,600-nm fractional laser therapy has been used with some success. The anti-androgen effect of Flutamide has been used with success in some patients. To read more about Becker Nevus click HERE and HERE.