Becker nevus syndrome.

The new term Becker nevus syndrome is proposed for a phenotype characterized by the presence of a particular type of organoid epithelial nevus showing hyperpigmentation, increased hairiness and hamartomatous augmentation of smooth muscle fibers, and other developmental defects such as ipsilateral hypoplasia of breast and skeletal anomalies including scoliosis, spina bifida occulta, or ipsilateral hypoplasia of a limb. The present review includes 23 cases that can be categorized under this designation. The Becker nevus syndrome usually occurs sporadically. The associated anomalies tend to show a definite regional correspondence, suggesting a common origin from an early postzygotic mutation.