Becker’s nevus is a sharply demarcated tan to brown patch or slightly raised verrucous plaque that most commonly appears on the shoulder, chest, or upper back. It typically presents unilaterally and is frequently associated with overlying hypertrichosis. It is a benign hamartoma.
Age: teens to thirties, rarely congenital, familial cases reported
Sex: males > females (6:1)
Precipitating factors: none
Unclear etiology. Postulated to have a localized increase in androgen receptors and heightened sensitivity to androgens.
There is papillomatosis, hyperkeratosis, acanthosis, and basal layer hyperpigmentation. There is an increase in the melanin content of keratinocytes with little or no change in the number of melanocytes. A smooth muscle hamartoma is frequently present in the dermis.
They occur most often on the upper trunk as a well-demarcated unilateral tan to dark brown patch with a block-like configuration ranging from a few to >15 cm. Hypertrichosis usually develops after the hyperpigmentation (Figs. 41.1 and 41.2). Acneiform lesions strictly limited to areas of hyperpigmentation have been reported.
Becker’s nevus. A slightly raised light-tan plaque with sharply defined and highly irregular border and hypertrichosis on the chest of a 35-year-old male (Wolff K, Johnson RA, Suurmond D. Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. New York: McGraw-Hill; 2005)
Becker’s nevus. Large brown plaque that becomes noticeable at puberty with increased pigment followed by hair growth (Wolff K, Johnson RA, Suurmond D. Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. New York: McGraw-Hill; 2005)
Congenital nevus, café au lait macule, epidermal nevus, plexiform neurofibroma
Physical examination should be performed to rule out associated hypoplasia of the ipsilateral arm, breast, areola, or ipsilateral arm shortening as well as pectus carinatum or thoracic scoliosis.
It most commonly presents at puberty as a unilateral tan patch. Over time, it may develop into a plaque and display a darker brown hue. Hair growth, which becomes darker and coarser over time, follows pigmentary changes. They tend to enlarge slowly for a few years, then remain stable over time. The color may fade with time; however, the hair growth usually persists.
KEY CONSULTATIVE QUESTIONS