INTRODUCTION
Becker nevus (BN) is a benign cutaneous smooth muscle hamartoma that presents with a hyperpigmented patch or plaque with or without hypertrichosis.1 BN may be associated with ipsilateral breast hypoplasia or other musculoskeletal abnormalities, an association which has been termed Becker nevus syndrome (BNS).2 It is believed that breast hypoplasia in BNS results from androgen’s antagonistic effect against estrogen, which normally stimulates pubertal breast development.3 Breast hypoplasia in BNS has been shown to improve with oral spironolactone treatment most likely due to spironolactone’s antiandrogenic effect.4,5 Herein we present an additional case of Becker nevus syndrome with a unilateral hypoplastic breast that improved with oral spironolactone treatment.
CASE REPORT
A thirteen-year-old female presented with a hyperpigmented plaque with a feathery border overlying a markedly hypoplastic left breast (Figure 1A). The plaque had been present for years, and the color had become darker since puberty. The patient had no history of precocious puberty or endocrine disorders. The patient’s height is within normal limits for her age. Physical examination revealed bilateral thumb hypoplasia and decreased left axillary hair. Breast ultrasonography revealed a hypoplastic left breast with normal breast parenchyma. Skin biopsy of the left breast demonstrated mild acanthosis with basilar hypermelanosis (Figure 2A, 2B). A trichrome stain highlighted
