Clinical Challenge: Coarse Hairs on the Back, Shoulder

Becker's nevus is a benign cutaneous melanocytic skin disorder. Clinically, the condition presents as a light brown macule with a geographic pattern and sharply demarcated borders. It can be present at birth, but often appears around the time of puberty...

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Becker’s nevus is a benign cutaneous melanocytic skin disorder. Clinically, the condition presents as a light brown macule with a geographic pattern and sharply demarcated borders.

It can be present at birth, but often appears around the time of puberty with a male to female ratio of 5:1. Becker’s nevus manifests unilaterally on the upper trunk and shoulder with fewer occurrences on the lower trunk and thighs.

Typically, the lesion extends for a variable time period and then remains stable in size, rarely fading. It can become darker and hairier throughout puberty, with one-half of cases having hypertrichosis.¹ Androgenic stimulation as an underlying factor has been postulated.²

Differential diagnoses include congenital melanocytic nevi, smooth muscle hamartomas, and café-au-lait macules. Histologic examination demonstrates normal number of melanocytes with increased levels of melanin in the basal epidermal layer.

Management of a Becker’s nevus is purely cosmetic and associated hypertrichosis can be managed with laser-assisted hair removal.³ Rates of malignancy are no different in Becker’s nevi when compared to normal skin.⁴

Congenital melanocytic nevi are small often singular melanocytic neoplasms that are present at birth. These lesions are generally darker than the surrounding skin and may be associated with hypertrichosis.⁵

Histologically, congenital nevomelanocytic nevi exhibit nevomelanocytic infiltration of the dermis and at times of underlying tissues. Large lesions carry a significant risk of melanoma. Treatment depends on the perceived risk of melanoma along with other cosmetic and functional considerations.⁶

Congenital smooth muscle hamartoma is a solitary patch or plaque most frequently found on the trunk. Lesions may be present at birth or arise during early infancy. Histology reveals sheets of smooth muscle cells. There is no malignant potential and surgical excision is curative.⁷

Café-au-lait spots are pigmented macules which are noted at birth or shortly thereafter and consist of heavily pigmented melanocytes originating from neural crest cells in the epidermis when numerous café-au-lait macules are included in the diagnostic criterion for NFT-1.⁸

Blake Shaffer, MBS, is a fourth year medical student at the Commonwealth Medical College, Scranton, Pennsylvania.

Stephen Schleicher, MD, is an associate professor of Medicine at the Commonwealth Medical College and an Adjunct Assistant Professor of Dermatology at the University of Pennsylvania Medical College. He practices dermatology in Hazleton, PA.

References

1. Tymen R, Forestier JF, Boutet B, Colomb D. [Late Becker’s nevus. One hundred cases (author’s transl)]. Ann Dermatol Venereol 1981; 108:41.
2. Person JR, Longcope C. Becker’s nevus: an androgen-mediated hyperplasia with increased androgen receptors. J Am Acad Dermatol 1984; 10:235.
3. Adatto M, Ben-Amitai D, Cohen S, Halachmi S, Lapidoth M. Hypertrichosis in Becker’s nevus: effective low-fluence laser hair removal. Lasers in Medical Science 2014. 29: 191-193.
4. Fehr B, Panizzon RG, Schnyder UW (1991). “Becker’s nevus and malignant melanoma”. Dermatologica 182 (2): 77-80.
5. Lapeere H, Boone B, De Schepper S, Verhaeghe E, Van Geel M, Ongenae K, Van Geel N, Lambert J, Brochez L. Chapter 75. Hypomelanoses and Hypermelanoses. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick’s Dermatology in General Medicine, 8e. New York, NY: McGraw-Hill; 2012.
6. Grichnik JM, Rhodes AR, Sober AJ. Chapter 122. Benign Neoplasias and Hyperplasias of Melanocytes. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick’s Dermatology in General Medicine, 8e. New York, NY: McGraw-Hill; 2012.
7. White LE, Levy RM, Alam M. Chapter 127. Neoplasias and Hyperplasias of Muscular and Neural Origin. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick’s Dermatology in General Medicine, 8e. New York, NY: McGraw-Hill; 2012.
8. Listernick R, Charrow J. Chapter 141. The Neurofibromatoses. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick’s Dermatology in General Medicine, 8e. New York, NY: McGraw-Hill; 2012.