How should an adolescent male with a hyperpigmented, hypertrichotic patch on the upper trunk (Becker's nevus) be evaluated and managed?

Management of Becker's Nevus in Adolescent Males

Becker's nevus is a benign cutaneous hamartoma requiring only clinical diagnosis and reassurance, with no routine investigations, imaging, or treatment necessary unless cosmetic concerns warrant intervention. 1, 2

Clinical Diagnosis

Becker's nevus presents as a hyperpigmented patch or plaque with hypertrichosis, typically appearing during adolescence on the upper trunk, shoulder, or proximal upper extremities in males (0.5% prevalence). 1, 2 The diagnosis is clinical and does not require biopsy unless the presentation is atypical. 1

Key Diagnostic Features to Confirm:

• Unilateral, irregularly shaped hyperpigmented patch (though rare bilateral cases exist) 1, 3
• Hypertrichosis (hair growth within the lesion) 1, 2
• Location: anterior upper body, shoulder, chest, or proximal arms 1, 2
• Timing: typically appears during or after puberty, though congenital cases occur rarely 1, 4
• Associated findings: occasional acneiform lesions within the nevus 1

Evaluation Algorithm

What to Assess:

• Screen for Becker's Nevus Syndrome (BNS): Examine for developmental abnormalities including ipsilateral breast hypoplasia, skeletal abnormalities (scoliosis, limb asymmetry), or smooth muscle hamartomas 1, 2
• No dermatoscopy, biopsy, or imaging required for typical presentations 1, 2
• Histology only if atypical: If biopsy is performed, expect elongation and fusion of rete ridges, keratotic plugging, sebaceous hyperplasia, smooth muscle hyperplasia, and basal/suprabasal hyperpigmentation 2

Critical Distinction from Congenital Melanocytic Nevus:

Becker's nevus is not a melanocytic lesion and carries no melanoma risk. 2 Unlike congenital melanocytic nevi, Becker's nevus does not require:

• Dermatology referral for melanoma surveillance 5, 6
• Serial photography or monitoring 5, 6
• MRI screening 5, 6
• Concern about malignant transformation 2

Management Approach

Reassurance is the Primary Management:

• Explain the benign nature: Becker's nevus is a hamartoma with no malignant potential 2
• Natural history: The lesion is permanent and may become more prominent with increased hair growth during puberty 1, 2
• No medical treatment required unless patient desires cosmetic improvement 2

Treatment Options (Only if Cosmetic Concerns Exist):

For hyperpigmentation:

• Q-switched lasers (Nd:YAG, alexandrite, ruby) have been attempted with variable and often temporary results 2
• Pigment frequently recurs after laser treatment 2

For hypertrichosis:

• Laser hair removal (diode, alexandrite, or Nd:YAG lasers) for permanent hair reduction 2
• Shaving, waxing, or electrolysis as alternatives 5

Common Pitfall to Avoid:

Do not confuse Becker's nevus with congenital melanocytic nevus. Becker's nevus is an epidermal hamartoma (not melanocytic), typically appears in adolescence (not congenital), and requires no melanoma surveillance or specialist referral. 1, 2 The hyperpigmentation in Becker's nevus is due to increased melanin in keratinocytes, not increased melanocytes. 2

Follow-Up

• No routine follow-up required 2
• Return only if: Patient develops concerns about associated developmental abnormalities (suggesting BNS) or desires cosmetic treatment 1, 2
• Genetic counseling: Rarely, Becker's nevus can be familial (autosomal dominant), though most cases are sporadic due to postzygotic ACTB mutations 4, 2