[4] Anomalies of the skin such as granuloma annulare, basal cell carcinoma, malignant melanoma, lymphangioma, osteoma cutis, and hypohidrosis have been observed to co-localize with Becker's nevus.
There have also been reports of quadriparesis, congenital adrenal hyperplasia, pectus carinatum, spina bifida, and an accessory scrotum.
[5] There have been several reports of ipsilateral developmental anomalies, including lipoatrophy,[6] segmental odontomaxillary dysplasia,[7] limb reduction,[8] aplasia of the pectoralis major muscle,[9] breast hypoplasia,[10] and supernumerary nipples.
[11] The majority of the diagnosis is clinical, with a well-defined area of hyperpigmentation and hypoplasia of the ipsilateral breast, areola and/or nipple, limb, muscle, and adipose tissue.
Histology results showing high androgen receptor levels in the hypoplastic muscles similar to those expressed in the genitalia further corroborate the diagnosis.