Becker's Nevus Syndrome in a Pediatric Female Patient.

Becker's nevus syndrome is part of the epidermal nevus syndromes and has been described with a phenotype that includes Becker's nevus, ipsilateral breast hypoplasia, and variable skeletal malformations. It is more frequent in males than in females (5 : 1) but is more relevant in females. The diagnosis is clinically based and the skin lesion must be present and no other numbered criteria have been established, but with more criteria being present the possibility of the diagnosis is higher.