Clinical Challenge: Deeply Pigmented Lesion on Upper Arm

Becker nevus was first described by William Becker in 1949 as concurrent melanosis and hypertrichosis in distribution of nevus unius lateris.1 It was subsequently referred to as Becker’s melanosis, Becker pigmentary hamartoma, nevoid melanosis, and pigmented hairy epidermal nevus.2 This benign lesion...

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Becker nevus was first described by William Becker in 1949 as concurrent melanosis and hypertrichosis in distribution of nevus unius lateris.¹ It was subsequently referred to as Becker’s melanosis, Becker pigmentary hamartoma, nevoid melanosis, and pigmented hairy epidermal nevus.² This benign lesion typically arises on the upper trunk of young men in the second or third decade of life.³ Occurrence on the lower trunk, extremities, and face also has been reported.⁴ Becker nevus syndrome is uncommon and is associated with unilateral breast hypoplasia and muscle, skin, and/or skeletal abnormalities.

Most cases of Becker nevus are believed to be acquired hamartomas. Some cases may result from an autosomal dominant inheritance pattern with incomplete penetrance and variable expressivity.⁵ The lesion commonly presents as ipsilateral hyperpigmented macules and patches with or without hypertrichosis.⁵ The hypertrichosis is the result of increased androgen receptor activity in dermal fibroblasts.⁶

The diagnosis of Becker nevus is usually made clinically, although biopsy may be necessary to differentiate the lesion from congenital melanocytic nevus.⁷ Congenital melanocytic nevi are present at birth and are typically darker in color, raised, have no anatomic predilection, and demonstrate melanocytic nevus cells on skin biopsy.⁸  Histology of Becker nevus reveals increased melanin content in keratinocytes, epidermal acanthosis, elongation and fusion of adjacent rete ridges, variable hyperkeratosis, and basal layer hyperpigmentation.⁹

Becker nevus is often of cosmetic concern and surgical excision is best avoided in favor of laser therapies that address both the hyperpigmentation and hypertrichosis.^10,11

Alexandra Stroia, BS, is a medical student at the Lake Erie College of Osteopathic Medicine. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Geisinger Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Becker SW. Concurrent melanosis and hypertrichosis in distribution of nevus unius lateris. Arch Derm Syphilol. 1949;60(2):155-160. doi:10.1001/archderm.1949.01530020023005

2. Zhong Y, Yang B, Huang L, Elias PM, Man MQ. Lasers for Becker’s nevus. Lasers Med Sci. 2019;34(6):1071-1079. doi:10.1007/s10103-019-02734-3

3. Cohen PR. Becker’s nevus. Am Fam Physician. 1988;37(5):221-226.

4. Moss C, Shahidullah H. Naevi and other developmental defects. In: Burns T, Breathnach S, Cox N, Griffiths C, eds. Rook’s Textbook of Dermatology. 8th ed. UK: Wiley-Blackwell; 2010:18.1-18.107.

5. Rao AG. Bilateral symmetrical congenital giant Becker’s nevus: a rare presentation. Indian J Dermatol. 2015;60(5):522. doi:10.4103/0019-5154.164441

6. Grande Sarpa H, Harris R, Hansen CD, Callis Duffin KP, Florell SR, Hadley ML. Androgen receptor expression patterns in Becker’s nevi: an immunohistochemical study. J Am Acad Dermatol. 2008;59(5):834-838. doi:10.1016/j.jaad.2008.06.028

7. Rivers J. Becker melanosis: background, pathophysiology, epidemiology. Emedicine.medscape.com. Updated May 24, 2018. Accessed June 8, 2022. https://emedicine.medscape.com/article/1068257-overview

8. Telang G, Criscione V. Becker’s nevus (Becker’s melanosis, Becker’s pigmentary hamartoma, nevoid melanosis, pigmented hairy epidermal nevus). Dermatology Advisor. Published March 13, 2019. Accessed June 8, 2022. https://www.dermatologyadvisor.com/home/decision-support-in-medicine/dermatology/beckers-nevus-beckers-melanosis-beckers-pigmentary-hamartoma-nevoid-melanosis-pigmented-hairy-epidermal-nevus/

9. Dasegowda SB, Basavaraj G, Nischal K, Swaroop M, Umashankar N, Swamy SS. Becker’s nevus syndrome. Indian J Dermatol. 2014;59(4):421. doi:10.4103/0019-5154.135530

10. Glaich AS, Goldberg LH, Dai T, Kunishige JH, Friedman PM. Fractional resurfacing: a new therapeutic modality for Becker’s nevus. Arch Dermatol. 2007;143(12):1488–1490. doi:10.1001/archderm.143.12.1488

11. Passeron T. Lasers. Ann Dermatol Venereol. 2012;139 Suppl 4:S159-S165. doi:10.1016/S0151-9638(12)70129-1