Gynaecomastia — the benign enlargement of glandular breast tissue in males — is more common than many people realise, yet questions about what it looks like and how to recognise it remain widespread. Visually, it typically presents as a rounded swelling beneath one or both nipples, giving the chest a softer, more contoured appearance. On examination, a firm, disc-like lump beneath the areola is the hallmark finding. Understanding the appearance of gynaecomastia helps distinguish it from other chest conditions, supports earlier GP assessment, and ensures that any serious underlying causes are not overlooked.

Recognising the Signs and Appearance of Gynaecomastia

Gynaecomastia appears as a rounded swelling beneath one or both nipples, with a firm, mobile, disc-like lump of glandular tissue palpable under the areola; early cases are often tender, whilst long-standing cases become fibrous.

Gynaecomastia is the benign enlargement of glandular breast tissue in males, and understanding what it looks like is the first step towards seeking appropriate care. Visually, it typically presents as a rounded swelling beneath one or both nipples, giving the chest a softer, more contoured appearance than is usual for male anatomy. Whilst the condition is often bilateral, unilateral presentation and noticeable asymmetry are common and should not be dismissed. In some cases the enlargement is subtle — a slight puffiness around the areola — whilst in others it can be more pronounced, resembling a small breast mound.

On physical examination, gynaecomastia feels distinctly different from surrounding chest tissue. The hallmark finding is a firm or rubbery disc of glandular tissue directly beneath the nipple-areola complex. This tissue is often described as feeling like a small button or lump. Tenderness and nipple sensitivity are typical features of early (proliferative) gynaecomastia, usually within the first six to twelve months of onset. Long-standing gynaecomastia tends to become less tender as glandular tissue is gradually replaced by fibrous tissue; this fibrotic stage responds poorly to medical treatment.

Key visual and physical features include:

• Bilateral or unilateral swelling beneath the nipple(s), often with some asymmetry

• Rounded, dome-shaped contour to the chest

• Firm, mobile, disc-like tissue palpable under the areola

• Mild tenderness or nipple sensitivity, particularly in early-stage disease

• Skin changes are uncommon — the overlying skin usually appears normal

Clinicians may use grading systems to classify severity — for example, the Simon classification — ranging from minor tissue enlargement without skin redundancy through to marked enlargement with excess skin. Recognising these features early helps distinguish gynaecomastia from other conditions and supports timely, appropriate assessment.

Further information is available from the NHS website (Gynaecomastia) and NICE Clinical Knowledge Summary (CKS): Gynaecomastia.

How Gynaecomastia Differs From Other Chest Conditions

Gynaecomastia is distinguished from pseudogynaecomastia by its firm subareolar disc; hard, fixed, or irregular lumps with skin changes or nipple discharge raise concern for male breast cancer and require urgent assessment.

Several conditions can cause chest swelling or lumps in males, so it is important to understand how gynaecomastia differs from other presentations. The most common condition confused with gynaecomastia is pseudogynaecomastia (also called lipomastia), which refers to fat deposition in the chest area without any true glandular tissue proliferation. Pseudogynaecomastia tends to feel soft and uniform, lacks the firm subareolar disc characteristic of true gynaecomastia, and is closely associated with being overweight or obese. It does not carry the same hormonal implications.

Another important distinction is male breast cancer, which, although rare, must always be considered when a new breast lump is identified. In line with NICE guidance (NG12: Suspected cancer — recognition and referral), features that should prompt urgent assessment include:

• A hard, irregular, or fixed lump that does not move freely

• Unilateral presentation, particularly in older men

• Nipple discharge, inversion, or skin changes such as dimpling or puckering

• Axillary lymph node enlargement

• Rapid or progressive growth of the lump

Men with Klinefelter syndrome have a significantly increased risk of male breast cancer; any new unilateral breast mass in this group warrants prompt clinical assessment.

Gynaecomastia, by contrast, is typically bilateral (though asymmetry is common), soft to firm, mobile, and centred directly beneath the nipple. It does not usually cause skin changes or nipple discharge.

Other conditions to consider include lipomas (benign fatty lumps that are soft and located away from the nipple), sebaceous cysts , and mastitis (breast tissue infection, which presents with redness, warmth, and systemic symptoms). A healthcare professional can usually differentiate these conditions through clinical examination, though imaging may be required. Any new or changing chest lump in a male should be assessed by a GP without delay.

See also: NICE NG12 (Suspected cancer: recognition and referral — breast); NHS website: Breast cancer in men.

Common Causes and Who Is Affected

Gynaecomastia results from an oestrogen–androgen imbalance and has three physiological peaks: neonatal, pubertal, and older age; medications, underlying conditions, and recreational drugs are also recognised causes.

Gynaecomastia arises from an imbalance between oestrogen and androgen activity in breast tissue. Oestrogens stimulate glandular proliferation, whilst androgens — primarily testosterone — suppress it. When this balance shifts, either through increased oestrogen, reduced testosterone, or increased sensitivity of breast tissue to oestrogen, gynaecomastia can develop.

It affects males across all age groups, with three recognised physiological peaks:

• Neonatal gynaecomastia: caused by maternal oestrogens crossing the placenta; typically resolves within weeks

• Pubertal gynaecomastia: affects up to 60% of adolescent boys during peak hormonal flux; usually resolves within 6–24 months

• Adult and older-age gynaecomastia: associated with declining testosterone levels and increasing body fat (which converts androgens to oestrogens via aromatisation)

Beyond physiological causes, a wide range of factors can contribute:

Medications are a particularly common cause. Well-recognised examples include:

• Anabolic steroids, testosterone therapy, and oestrogen-containing products

• Anti-androgens (e.g., bicalutamide, cyproterone acetate)

• 5-alpha-reductase inhibitors (e.g., finasteride, dutasteride)

• Spironolactone and digoxin

• Ketoconazole and cimetidine

• Some antiretrovirals (e.g., efavirenz)

• Prolactin-raising antipsychotics (e.g., risperidone, haloperidol); antidepressant-associated gynaecomastia is uncommon and evidence is limited

• Chemotherapy agents

• Cannabis and some other recreational drugs

Note: proton pump inhibitors (PPIs) are occasionally cited in case reports, but the evidence linking them to gynaecomastia is limited and they are not routinely listed as a cause in current UK guidance.

Important: if you suspect a prescribed medicine may be contributing to gynaecomastia, do not stop or alter your medication without first speaking to your GP or pharmacist. Suspected adverse drug reactions can be reported via the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Underlying medical conditions associated with gynaecomastia include hypogonadism, hyperthyroidism, chronic liver disease (cirrhosis), chronic kidney disease, and rarely, oestrogen- or hCG-secreting tumours. Klinefelter syndrome is also a recognised cause.

In many cases — particularly in adolescents and older men — no specific underlying cause is identified, and the condition is classified as idiopathic gynaecomastia. A thorough medication review and clinical history remain essential first steps in identifying any reversible contributing factors.

Further information: NICE CKS: Gynaecomastia; BNF (online) — adverse effects sections for implicated medicines; MHRA/emc SmPCs.

When to See a GP and What to Expect

Any new male breast lump should be assessed by a GP; urgent two-week wait referral is required if features suggest malignancy, such as a hard fixed lump, nipple discharge, or skin changes.

Most cases of gynaecomastia are benign and self-limiting, but it is always advisable to seek a GP assessment when breast tissue enlargement is noticed in a male. Early review helps exclude serious underlying causes, provides reassurance, and ensures appropriate management is initiated if needed.

Contact your GP promptly if you notice:

• A new lump or swelling in the chest or breast area

• Rapid or progressive enlargement of breast tissue

• A hard, irregular, or fixed lump

• Nipple discharge, inversion, or skin changes (e.g., dimpling or puckering)

• Breast changes accompanied by other symptoms such as fatigue, unexplained weight loss, or testicular changes

• Significant psychological distress related to the appearance of your chest

At the appointment, your GP will take a detailed history, including your age, duration of symptoms, any relevant medications, recreational drug use, and family history. They will perform a focused physical examination of the chest, abdomen, and testes to look for signs of underlying pathology.

If the presentation is straightforward — for example, a teenager with classic pubertal gynaecomastia of less than six to twelve months' duration and no red-flag features — the GP may offer reassurance and a period of watchful waiting without immediate investigation. However, if there is clinical uncertainty, features suggesting an underlying cause, or any concern about malignancy, onward referral or investigation will be arranged.

In line with NICE NG12 guidance, GPs should refer men urgently via the two-week wait (2WW) suspected cancer pathway if they present with a suspicious breast mass, unexplained unilateral nipple discharge or retraction, or other features raising concern for malignancy. This pathway applies to males as well as females. Patients should feel empowered to raise concerns and ask questions during their consultation.

See also: NICE NG12 (Suspected cancer: recognition and referral); NICE CKS: Gynaecomastia; NHS website: Gynaecomastia.

Diagnosis and Assessment on the NHS

NHS assessment follows a triple assessment model — clinical examination, ultrasound (first-line imaging), and targeted blood tests — with urgent two-week wait referral for any suspicious unilateral or rapidly growing breast mass.

The diagnostic process for gynaecomastia on the NHS is guided by clinical findings and the need to exclude serious underlying pathology. After an initial GP assessment, patients may be referred to an endocrinologist, general surgeon, or symptomatic breast clinic depending on the clinical picture.

In symptomatic breast clinics, assessment typically follows a triple assessment model, comprising clinical examination, imaging, and — where indicated — tissue sampling. In men, ultrasound is generally the first-line imaging modality and can reliably distinguish glandular tissue from fat, as well as identify suspicious features. Mammography may be added when malignancy is a concern, particularly in older men or where clinical findings are equivocal. The choice of imaging modality is guided by the patient's age and the degree of clinical suspicion.

Blood tests are targeted by clinical history and examination findings, and may include:

• Liver function tests (to assess for hepatic causes)

• Renal function (to exclude chronic kidney disease)

• Thyroid function tests

• Testosterone, LH, FSH, and oestradiol (to evaluate the hormonal axis)

• Prolactin (elevated in some pituitary conditions)

• hCG and AFP (tumour markers if a testicular or adrenal tumour is suspected)

Further imaging — such as testicular ultrasound, CT, or pituitary MRI — is reserved for cases where blood test results are abnormal or there is strong clinical suspicion of an underlying structural cause.

NICE NG12 guidance and NHS breast referral pathways emphasise that any male with a unilateral, hard, or rapidly growing breast lump should be referred urgently under the two-week wait cancer pathway. For straightforward cases of gynaecomastia, a diagnosis is often made clinically, and extensive investigation may not be necessary. The goal of assessment is to confirm the diagnosis, identify any treatable underlying cause, and guide appropriate management.

See also: NICE CKS: Gynaecomastia (investigations); NICE NG12; NHS website: Breast cancer in men (diagnosis).

Treatment Options and Managing Gynaecomastia

Watchful waiting is appropriate for physiological gynaecomastia; addressing the underlying cause is the first priority, with off-label tamoxifen considered in specialist settings for early cases, and surgery reserved for established or distressing gynaecomastia.

The management of gynaecomastia depends on its underlying cause, severity, duration, and the degree of distress it causes. In many cases — particularly physiological gynaecomastia in adolescents — watchful waiting is the most appropriate initial approach, as spontaneous resolution is common within one to two years.

Addressing the underlying cause is always the first priority. If a causative medication is identified, the GP or specialist may consider switching to an alternative where clinically safe to do so. Patients should not stop or change any prescribed medicine without first discussing this with their clinician. Treating an underlying condition such as hyperthyroidism or hypogonadism may also lead to regression of breast tissue, particularly if the gynaecomastia is of recent onset — generally within the first twelve months, before fibrous tissue replaces glandular tissue. Long-standing fibrotic gynaecomastia is unlikely to respond to medical treatment.

Medical therapy is not routinely recommended on the NHS for gynaecomastia but may be considered in specialist settings for persistent or painful early-stage cases:

• Tamoxifen (a selective oestrogen receptor modulator, or SERM) may be used off-label — it does not have a UK marketing authorisation for gynaecomastia — and can reduce glandular tissue in the early proliferative phase. Its use should be specialist-led, with shared decision-making and discussion of potential adverse effects, which include venous thromboembolism (VTE), hot flushes, and other effects listed in the MHRA-approved Summary of Product Characteristics (SmPC).

• Aromatase inhibitors such as anastrozole have also been studied, though evidence remains limited and their use is not standard practice in the UK.

If you experience a suspected side effect from any medicine used in the management of gynaecomastia, this can be reported via the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Experiencing these side effects? Our pharmacists can help you navigate them →

Surgical treatment is the most definitive option for established gynaecomastia that has not responded to conservative measures, or where fibrous tissue is present. Options include:

• Subcutaneous mastectomy (surgical excision of glandular tissue)

• Liposuction (for cases with a significant fat component)

• A combination of both techniques

Surgery on the NHS is generally reserved for cases causing significant psychological distress or functional impairment, and access may vary by Integrated Care Board (ICB). Patients should discuss the full range of options with their GP or specialist, including realistic expectations of each approach and any associated risks.

See also: NICE CKS: Gynaecomastia (management); BNF (online): Tamoxifen; MHRA/emc SmPC for tamoxifen; NHS/ICB policies on surgery for gynaecomastia.

Frequently Asked Questions