TLDR A 16-year-old boy had a rare case of Becker's nevus on his face and mouth.
Becker’s nevus, also known as Becker’s pigmented hairy nevus, is a common melanotic epidermal hypermelanosis typically presenting as a large unilateral patch of hyperpigmentation and hypertrichosis on the shoulder, chest, or back of adult men. This report described a rare case of a 16-year-old boy with two Becker’s nevi on the left side of his face in a segmental distribution, extending onto the oral mucosa. This unusual presentation highlighted the potential for Becker’s nevi to appear in atypical locations and configurations.
November 2019 in “Harper's Textbook of Pediatric Dermatology” The document is a detailed medical reference on skin and genetic disorders.
[object Object] 
1 citations,
March 2004 in “Journal of The European Academy of Dermatology and Venereology” Hair loss improved with treatment and successful transplant.
March 2014 in “Journal of The American Academy of Dermatology” The document lists various dermatology topics, treatments, and diagnostic methods.
June 2006 in “British Journal of Dermatology” The document reports unique growth lines in a child after Stevens-Johnson syndrome, skin reaction from parsnips and sun in a girl, and itchy skin with xanthomas in a boy with Alagille syndrome.
32 citations,
April 1994 in “Journal of the American Academy of Dermatology” High androgen levels and genetic factors likely cause Becker's nevus and related symptoms.
