Becker nevus syndrome

What it is

From: Orphanet

A rare, syndromic, benign, epidermal nevus syndrome characterized by the association of a Becker nevus (i.e. circumscribed, unilateral, irregularly shaped, hyperpigmented macules, with or without hypertrichosis and/or acneiform lesions, occuring predominantly on the anterior upper trunk or scapular region) with ipsilateral breast hypoplasia or other, typically hypoplastic, skeletal, cutaneous, and/or muscular defects, such as pectoralis major hypoplasia, supernumerary nipples, vertebral defects, scoliosis, limb asymmetry, odontomaxillary hypoplasia and lipoatrophy.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Hamartoma · Very frequent (99-80%)

A disordered proliferation of mature tissues that is native to the site of origin, e.g., exostoses, nevi and soft tissue hamartomas. Although most hamartomas are benign, some histologic subtypes, e.g., neuromuscular hamartoma, may proliferate aggressively such as mesenchymal cystic hamartoma, Sclerosing epithelial hamartoma, Sclerosing metanephric hamartoma.

Hypermelanotic macule · Very frequent (99-80%)

A hyperpigmented circumscribed area of change in normal skin color without elevation or depression of any size.

Lipoatrophy · Very frequent (99-80%)

Localized loss of fat tissue.

Micromelia · Very frequent (99-80%)

The presence of abnormally small extremities.

Shoulder girdle muscle atrophy · Very frequent (99-80%)

Amyotrophy affecting the muscles of the shoulder girdle.

Supernumerary nipple · Very frequent (99-80%)

Presence of more than two nipples.

Aplasia/Hypoplasia of the breasts · Frequent (79-30%)

Absence or underdevelopment of the breasts.

Pectus carinatum · Frequent (79-30%)

A deformity of the chest caused by overgrowth of the ribs and characterized by protrusion of the sternum.

Pectus excavatum · Frequent (79-30%)

A defect of the chest wall characterized by a depression of the sternum, giving the chest ("pectus") a caved-in ("excavatum") appearance.

Abnormality of the scrotum · Occasional (29-5%)

Any structural abnormality of the scrotum, i.e., the sac that contains the testes, epididymis, and the lower part of the spermatic cord.

Abnormality of tibia morphology · Occasional (29-5%)

Abnormality of the tibia (shinbone).

Kyphosis · Occasional (29-5%)

Exaggerated anterior convexity of the thoracic vertebral column.

Lower limb asymmetry · Occasional (29-5%)

A difference in length or diameter between the left and right leg.

Rib fusion · Occasional (29-5%)

Complete or partial merging of adjacent ribs.

Other findings in the same source

From: Orphanet

Additional reported features include Scoliosis (Occasional (29-5%)); Spina bifida occulta (Occasional (29-5%)); Supernumerary ribs (Occasional (29-5%)); Upper limb asymmetry (Occasional (29-5%)); Hypoplastic labia minora (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Point prevalence: Unknown; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Becker nevus syndrome is Dermatology, with a dermatologist as the relevant type of clinician. Dermatologist; paediatric services for children as appropriate.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which features of the skin, hair or nails distinguish the possibilities?
• Would photographs over time help document the changes?
• What should be expected from treatment, and how will irritation or other adverse effects be managed?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Becker nevus syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.