Gynaecomastia and male breast symptoms

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Gynaecomastia is benign proliferation of male ductal and stromal breast tissue caused by increased oestrogenic effect relative to androgenic effect at the breast. It may be unilateral or bilateral and often presents as a tender, rubbery subareolar disc. Obesity can coexist and increase aromatisation, but soft diffuse fat alone is not glandular gynaecomastia. Pubertal disease commonly resolves, whereas recent adult onset deserves a directed search for medicines, substances and endocrine, hepatic, renal or testicular disease.

Male breast cancer is uncommon but must remain visible in the differential because diagnostic delay occurs when every male breast symptom is dismissed. Central tender tissue favours gynaecomastia, while a hard eccentric lesion, nipple change, discharge or nodes is concerning. Imaging and core biopsy follow specialist assessment when examination is atypical. Management then addresses cause and burden: remove a reversible exposure safely, treat underlying disease, observe likely physiological change, or discuss surgery when established tissue creates persistent symptoms or distress.

Key points

True gynaecomastia is palpable benign glandular tissue extending concentrically beneath the nipple-areolar complex; diffuse fat without a glandular disc is pseudogynaecomastia.
Physiological peaks occur in neonates, puberty and older age, but new adult-onset disease requires a medicine, substance and systemic-cause review.
Representative contributors include spironolactone, bicalutamide or other anti-androgens, finasteride or dutasteride, cimetidine, some antipsychotics, opioids and anabolic steroids; essential treatment is changed only with its prescriber.
A hard eccentric mass, skin fixation, nipple retraction or discharge, ulceration or abnormal axillary node requires breast-cancer assessment rather than attribution to gynaecomastia.
Testicular examination and targeted liver, renal, thyroid and hormone tests are guided by history, asymmetry, rapid progression or signs of hypogonadism or hormone-secreting tumour.
Observation and treatment of the cause suit many cases; persistent pain or major psychosocial harm may justify specialist medical or surgical discussion after diagnostic safety is established.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Physiological hormone balance

Transient relative oestrogen effect occurs in neonatal, pubertal and older-age physiology and can stimulate benign ductal and stromal proliferation.

Medicines substances and disease

Anti-androgenic or oestrogenic medicines, anabolic steroids, liver or renal disease, thyroid excess, hypogonadism and hormone-secreting tumours can shift the balance.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Relative oestrogenic stimulation
Increased oestrogen action or reduced androgen action activates male breast ducts and periductal stroma, which normally remain rudimentary.
2
Proliferative tender phase
Early epithelial proliferation, stromal oedema and inflammation form a tender subareolar disc that may regress when the stimulus disappears.
3
Late stromal fibrosis
With time, collagen deposition replaces active proliferation and produces established firm tissue that is less responsive to causal removal or medical therapy.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Subareolar glandular disc

Firm or rubbery tissue centred directly beneath the areola and extending concentrically supports gynaecomastia. Recent proliferative tissue may be tender, especially in puberty or after a medicine change.

Pseudogynaecomastia

Diffuse soft adipose fullness without a discrete retroareolar disc suggests fat distribution. Examination should still search for a separate focal mass hidden within larger breasts.

Cancer warning features

An eccentric hard mass, skin tethering, new nipple inversion, ulceration, bloody discharge or axillary nodes is not explained adequately by symmetrical glandular enlargement.

Cause-directed clues

Spironolactone for heart failure, anti-androgens, 5-alpha-reductase inhibitors, cimetidine, antipsychotics, opioids and anabolic substances are representative exposures. Reduced libido, testicular change, thyroid symptoms or liver disease direct the subsequent investigation.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Breast and nodal examinationFirst step
Why
Distinguish subareolar glandular tissue from an eccentric suspicious lesion and adiposity.
Interpretation and limitations
Typical bilateral central tissue may need no imaging. A discrete, hard or asymmetric target and any nipple or nodal sign enters the specialist breast pathway.
02
Medicine and substance reconciliation
Why
Identify a temporal cause without compromising essential treatment.
Interpretation and limitations
Record prescribed, non-prescribed and performance-enhancing agents, alcohol and cannabis exposure. Causation is stronger when onset follows exposure and no red flags suggest another process.
03
Source-specific unexplained-adult blood and testicular branch
Why
Identify endocrine, organ and tumour-marker causes after history and examination fail to show a clear physiological or medicine explanation.
Interpretation and limitations
Obtain 9 am testosterone, thyroid function, liver function, alpha-fetoprotein and beta-hCG. If testosterone is abnormal, add LH, FSH, SHBG, albumin, oestradiol and prolactin. Perform testicular ultrasound for an abnormal examination or raised beta-hCG/AFP; refer abnormal tumour markers or ultrasound urgently to urology and other endocrine abnormalities to endocrinology.
04
Mammography ultrasound and core
Why
Diagnose an atypical male breast mass and sample suspicious tissue.
Interpretation and limitations
Imaging can show the characteristic glandular pattern, but a solid eccentric lesion or discordant finding requires representative core biopsy just as in other breast assessment.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Pseudogynaecomastia

Diffuse adipose enlargement lacks a firm concentric glandular disc but can coexist with true tissue and conceal a focal lesion.

Male breast carcinoma

A hard eccentric mass, fixation, nipple change, discharge or nodes raises concern and requires triple assessment with representative core tissue.

Benign focal mass

Lipoma, cyst, abscess, epidermal lesion and other benign masses can present in male breast tissue and are localised by examination and imaging.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Medicine-associated pathwayReview spironolactone without destabilising heart failureFirst stepA 67-year-old develops tender bilateral subareolar glandular tissue three months after starting spironolactone for heart failure, with no eccentric mass, nipple change, node or endocrine warning feature.

1Confirm true concentric glandular enlargement and reconcile the timing of spironolactone, dose changes, other prescribed medicines and non-prescribed substances.
2AlternativeExplain that spironolactone is a recognised contributor, but do not stop or reduce it independently; ask the heart-failure prescriber whether an evidence-based alternative or dose strategy is clinically acceptable for this individual.
3If the heart-failure team authorises a change, document the replacement and monitoring needed for the cardiac indication rather than treating breast improvement as the only outcome.
4Review tenderness, subareolar diameter and cardiac stability. Reopen breast or endocrine assessment if tissue enlarges, becomes eccentric or persists despite removal of the likely trigger.

02Suspicious-mass pathwayDo not hide cancer behind a benign labelA 72-year-old man has a hard 2 cm mass lateral to the nipple, recent inversion and a palpable axillary node.

1Document exact mass position and nipple, skin and node findings, while asking about duration, family history, previous chest radiation and systemic symptoms.
2Arrange urgent breast assessment with mammography, ultrasound and image-guided core of the mass and abnormal node when indicated.
3Avoid describing the lesion as gynaecomastia because its eccentric fixed phenotype does not match a concentric glandular disc.
4Ensure pathology, imaging and examination are reconciled at the breast multidisciplinary meeting and communicate one integrated outcome.

03Persistent pubertal pathwayUse the expected horizon without ignoring atypical diseaseA 16-year-old has bilateral tender glandular discs for 9 months and is avoiding school sport, with normal puberty and no concerning examination findings.

1Confirm pubertal development, duration, medicines and supplements, and examine breasts and testes respectfully with consent and safeguarding awareness.
2Explain that physiological pubertal gynaecomastia commonly resolves and arrange review, while treating pain, bullying, body-image distress and functional avoidance as meaningful outcomes.
3Seek earlier paediatric, endocrine or breast input for massive or rapid enlargement, atypical puberty, a testicular finding, hard eccentric tissue, nipple or nodal change, severe pain or distress, or another systemic clue.
4Refer persistent adolescent gynaecomastia that remains beyond 18 to 24 months for specialist assessment rather than extending reassurance indefinitely.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Persistent pain

Active proliferative tissue can remain tender, limiting exercise, sleep position and clothing even without a dangerous underlying cause.

Psychosocial harm

Body-image distress, embarrassment, bullying and avoidance of relationships or sport can be severe and should be documented rather than minimised.

Surgical contour problems

Excision or liposuction can cause haematoma, asymmetry, crater deformity, altered nipple sensation or conspicuous scars requiring realistic consent.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Record laterality, subareolar diameter, tenderness and functional or psychological effect so progression and response are assessed consistently.
After changing a suspected medicine, verify the prescriber-approved replacement remains effective for its original indication and that breast symptoms stabilise.
Review new testicular, nipple, skin or nodal findings urgently rather than waiting for a routine gynaecomastia appointment.
After surgery, assess haematoma, seroma, nipple sensation, contour irregularity and scar impact as well as symptom relief.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Tenderness reflects timing

Early proliferative glandular tissue is often sore, while longstanding fibrotic tissue may be painless and less likely to regress after removing the cause.

Obesity can contribute twice

Adipose tissue creates pseudogynaecomastia and increases aromatisation of androgens to oestrogens, so a patient can have both fat fullness and a true glandular disc.

The testes are relevant

A testicular tumour may alter beta-hCG or sex-steroid balance before causing prominent local symptoms. Testicular examination belongs in unexplained rapid adult-onset disease.

Distress is a real outcome

Benign biology does not mean trivial impact. Pain, shame and avoidance warrant sensitive inquiry and can influence referral after serious causes are excluded.

11Common pitfallsFrequent interpretation and management errors.

01
Calling diffuse obesity gynaecomastia without feeling for a glandular disc or separate mass obscures the actual anatomy.
02
Stopping a suspected essential medicine abruptly can destabilise the condition for which it was prescribed and should not be advised independently.
03
Reassuring an older man with an eccentric hard mass and nipple change as hormonal breast growth delays cancer diagnosis.
04
Ordering a broad hormone panel without clinical direction can distract from a suspicious breast target that needs imaging and core biopsy.

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