Background: Becker nevus (BN) is a unilateral, hairy, pigmented cutaneous hamartoma that frequently appears in adolescence. Several features of BN suggest that increased androgen sensitivity plays a role in its pathogenesis. There have been only a few studies of histopathologic and immunohistochemical characteristics of BN, and the etiopathogenesis has not been fully established.
Methods: Two-millimeter punch biopsies were taken from lesional and perilesional normal skin of 30 patients diagnosed as having BN. Fifteen skin samples each of lentigo and café au lait spots were used as controls. The sections were stained with hematoxylin-eosin, Fontana-Masson, antibodies to NKI/beteb, MART-1 (Melanoma Antigen Recognized by T cells), S-100 protein and androgen receptor (AR).
Results: Histopathologic features of BN showed frequent acanthosis, papillomatosis, keratotic plugging, irregular rete ridge elongation and flattening in the epidermis. Especially, the shape of the rete ridges in BN had a relatively characteristic appearance, which was the fusion of more than two adjacent rete ridges. Melanocyte counts were significantly increased in BN skin. The extent of AR expression was significantly higher in the epidermis of BN.
Conclusions: Our study indicates that there may be an association between AR and BN, but additional studies will be required to evaluate this further.