๐ Key Information Summary
- Definition: Gynaecomastia is benign proliferation of glandular breast tissue in males resulting from a relative or absolute oestrogen-to-androgen imbalance at the breast tissue level.
- Prevalence: Present in up to 65% of males on physical examination; clinically significant in approximately 30โ40% across the lifespan, with peaks in neonatal/pubertal and older age groups.
- Physiological gynaecomastia: Neonatal (transplacental oestrogen), pubertal (affects up to 60% of adolescent boys; 90% resolve within 2 years), and senescent (ageing-related androgen decline) โ these generally require no investigation or treatment.
- Pathological causes: Always exclude hypogonadism (primary or secondary), hyperthyroidism, liver cirrhosis, chronic kidney disease, and drug-induced gynaecomastia (spironolactone, antiandrogens, oestrogens, digoxin, cimetidine, and many psychotropic medications).
- Red flags for malignancy: Unilateral, hard, irregular mass; fixed to underlying tissue; axillary lymphadenopathy; nipple retraction or skin changes โ these warrant urgent mammography/ultrasound and surgical referral.
- Simon grading: Grade I (small, localised), Grade IIa (moderate, not exceeding areola), Grade IIb (extending beyond areola), Grade III (large, female-appearing) โ guides management approach.
- Baseline investigations: Serum testosterone (total and free), oestradiol, LH, FSH, TSH, hCG (ฮฒ-subunit), liver function tests, renal function (eGFR), prolactin, and SHBG in all non-physiological presentations.
- First-line medical therapy: Testosterone replacement for hypogonadal men; tamoxifen 20 mg daily for 3โ6 months for symptomatic gynaecomastia (PBS Authority Required for this indication).
- Surgical referral: Indicated for long-standing (>12 months) gynaecomastia with fibrotic tissue, significant psychological distress, or failed medical therapy โ techniques include liposuction and subcutaneous mastectomy.
- Drug review: A thorough medication history is essential; up to 25% of cases are drug-related โ if a causative agent is identified, cessation or substitution is the first management step.
- Breast cancer in males: Rare (<1% of all breast cancers) but must be considered, especially in older men with unilateral firm mass and risk factors (family history, BRCA2, Klinefelter syndrome).
- Follow-up: Physiological gynaecomastia โ reassurance and observation every 3โ6 months; pathological โ repeat hormonal profile at 3โ6 months after treatment initiation; surgical โ standard post-operative review.
๐ง Audio Brief
Introduction & Australian Epidemiology
Gynaecomastia is the benign proliferation of glandular breast tissue in males, resulting from an imbalance between oestrogen and androgen activity at the level of the breast. It is the most common breast condition encountered in male patients and presents across all age groups. Although often benign and self-limiting, gynaecomastia may be the presenting feature of serious underlying endocrine, hepatic, renal, or neoplastic pathology and requires systematic evaluation.
In Australia, gynaecomastia is commonly encountered in general practice, paediatrics, and endocrinology clinics. The Royal Children's Hospital Melbourne reports that up to 60% of pubertal boys develop palpable breast tissue, with the majority resolving spontaneously within 18โ24 months. Among older Australian men, cross-sectional data suggest clinically detectable gynaecomastia in approximately 35โ40% of men aged 50โ80 years, driven by declining testosterone levels, increased adipose tissue aromatase activity, and concurrent medication use.
Drug-induced gynaecomastia is particularly relevant in the Australian context, with spironolactone (widely prescribed for heart failure and resistant hypertension), antiandrogens for prostate cancer, and increasingly used antipsychotic medications representing major causative agents. Aboriginal and Torres Strait Islander males may face a disproportionate burden due to higher rates of chronic kidney disease, liver disease, and delayed access to specialist endocrine evaluation (AIHW, 2023).
This guideline provides an evidence-based framework for the evaluation and management of gynaecomastia in Australian clinical practice, aligned with the Endocrine Society of Australia, the RACGP Red Book, and international consensus statements.
Pathophysiology & Causes
Mechanism
Gynaecomastia results from a shift in the oestrogen-to-androgen ratio favouring oestrogenic stimulation of breast ductal tissue. Oestrogen acts via oestrogen receptors (ER-ฮฑ and ER-ฮฒ) on ductal epithelium, promoting ductal proliferation, periductal stromal oedema, and eventual fibrosis. Androgens (primarily testosterone and dihydrotestosterone) normally oppose this effect; their reduction or the increase in oestrogen activity tips the balance toward tissue growth.
The oestrogen excess may be:
- Absolute: Elevated serum oestradiol โ from testicular or extragonadal tumours, exogenous oestrogen exposure, or increased peripheral aromatisation (obesity, liver cirrhosis, thyrotoxicosis).
- Relative: Decreased androgen levels with stable oestrogen โ from primary hypogonadism (Klinefelter syndrome, orchidectomy), secondary hypogonadism (pituitary disease), or androgen receptor blockade (spironolactone, bicalutamide).
Causes by Category
| Category | Examples | Mechanism |
|---|---|---|
| Physiological | Neonatal, pubertal, senescent | Transient hormonal fluctuations; self-limiting |
| Hypogonadism | Klinefelter syndrome (47,XXY), orchitis (mumps), post-gonadectomy, Kallmann syndrome, pituitary adenoma | Decreased testosterone with preserved/gonadotrophin-stimulated oestradiol |
| Hyperoestrogenaemia | Testicular tumours (Leydig cell, Sertoli cell), hCG-secreting tumours (hepatocellular, mediastinal germ cell), adrenal tumours | Direct oestrogen or hCG-mediated oestradiol production |
| Peripheral aromatisation | Obesity, liver cirrhosis, hyperthyroidism | Increased adipose aromatase converting androgens to oestrogens |
| Drug-induced | Spironolactone, bicalutamide, flutamide, finasteride, oestrogens (topical HRT transfer), digoxin, cimetidine, ranitidine, phenothiazines, risperidone, olanzapine, SSRIs, methotrexate, isoniazid, anabolic steroids, marijuana, alcohol excess | Oestrogen activity, androgen blockade, or direct receptor effects |
| Chronic disease | Chronic kidney disease (uraemia), dialysis | Hypogonadism, altered SHBG, increased aromatisation |
Spironolactone is the most commonly implicated drug in Australian practice. Up to 10โ15% of men on spironolactone develop gynaecomastia. Consider switching to eplerenone (selective aldosterone antagonist, less antiandrogenic activity) if gynaecomastia is intolerable, particularly in heart failure patients.
Clinical Features & Grading
Presentation
Gynaecomastia typically presents with:
- Palpable, rubbery, disc-like subareolar tissue โ often tender, especially in florid (early) cases
- Bilateral in 50โ70% of cases; unilateral raises concern for malignancy or asymmetric disease
- May be associated with breast discomfort, nipple sensitivity, or psychological distress (body image, social avoidance)
- On examination: tissue centred under the nipple, may extend concentrically; compressible from the periphery compared to surrounding adipose tissue
Simon Classification
Grade I
Small
Small breast enlargement, localised to the areolar region; no excess skin
Often physiological or early pathological; observation or medical therapy
Grade IIa
Moderate
Moderate enlargement not exceeding the boundaries of the areola; no excess skin
Common presentation; targeted investigation and medical or surgical therapy
Grade IIb
Moderate Extended
Moderate enlargement exceeding the areolar diameter; minimal excess skin
Often requires combination therapy; consider early surgical referral
Grade III
Large
Marked enlargement with excess skin, resembling female breast ptosis
Surgical referral indicated; liposuction ยฑ mastectomy
Duration Considerations
The duration of gynaecomastia affects tissue composition and response to medical therapy:
- Florid phase (0โ6 months): Proliferating ducts, periductal oedema, and increased vascularity โ most responsive to medical therapy
- Intermediate phase (6โ12 months): Progressive fibrosis; decreasing oedema; moderately responsive to treatment
- Fibrous phase (>12 months): Dense fibrosis and hyalinisation of stroma; minimal response to medical therapy โ surgical excision generally required
Distinguishing Gynaecomastia from Other Conditions
| Feature | Gynaecomastia | Lipomastia (Pseudogynaecomastia) | Male Breast Cancer |
|---|---|---|---|
| Palpation | Firm, rubbery, disc-like tissue under areola | Soft, diffuse adipose; no discrete disc | Hard, irregular, eccentric mass |
| Laterality | Bilateral (50โ70%) | Usually bilateral, symmetrical | Usually unilateral |
| Tenderness | Common (florid phase) | Absent | Variable; may be painless |
| Skin/nipple changes | Rare | Absent | Retraction, dimpling, ulceration, discharge |
| Lymphadenopathy | Absent | Absent | May be present (axillary) |
Investigations & Differential
Investigations Pathway
Investigation should be directed by clinical assessment. Physiological gynaecomastia (neonatal, pubertal, senescent) in the absence of red flags generally requires no laboratory workup. All pathological presentations require a structured approach.
First-Line Investigations (all non-physiological cases)
Essential
Serum total testosterone (morning, fasting)
MBS Item 66596. Low (<8 nmol/L) suggests hypogonadism; normal or high requires further workup.
Essential
Free testosterone (calculated or equilibrium dialysis)
MBS Item 66596. Calculate using Vermeulen equation when SHBG is measured. Identifies bioavailable testosterone.
Essential
Serum oestradiol (high-sensitivity assay)
MBS Item 65070. Elevated levels suggest oestrogen-secreting tumour or increased aromatisation.
Essential
LH and FSH
MBS Item 65200 / 65201. Differentiates primary (elevated) from secondary (low/inappropriate) hypogonadism.
Essential
ฮฒ-hCG
MBS Item 65295. Detects hCG-secreting germ cell tumours (testicular, mediastinal, hepatic).
Essential
TSH ยฑ free T4
MBS Item 66722. Excludes hyperthyroidism (increases SHBG, oestrogen production).
Available
Liver function tests (LFTs)
Standard panel. Assess for cirrhosis, hepatocellular carcinoma.
Available
Renal function (eGFR) and urea
Standard panel. Exclude CKD as contributing cause.
Available
Prolactin
MBS Item 66656. Elevated in prolactinoma, drug-induced (antipsychotics, metoclopramide).
Available
SHBG (sex hormone-binding globulin)
MBS Item 66880. Assists free testosterone calculation; elevated in hyperthyroidism, liver disease.
Second-Line Investigations (targeted)
Specialist-directed
Testicular ultrasound
If ฮฒ-hCG elevated, asymmetric testicular findings, or unexplained oestradiol elevation โ excludes Leydig/Sertoli cell tumours.
Specialist-directed
Mammography ยฑ breast ultrasound
For any unilateral mass suspicious for malignancy. Mammography sensitivity for male breast cancer ~92%. Ultrasound useful for distinguishing solid vs cystic in younger patients.
Specialist
CT chest/abdomen/pelvis
If hCG-secreting extragonadal germ cell tumour suspected or adrenal pathology identified on biochemistry.
Specialist
Karyotype (47,XXY)
Klinefelter syndrome screening in tall, eunuchoid men with small testes and elevated gonadotrophins. Affects ~1 in 600 males.
Specialist
Adrenal androgens (DHEA-S, androstenedione, 17-OH progesterone)
If adrenal tumour suspected or CAH (congenital adrenal hyperplasia) considered.
Differential Diagnosis
| Diagnosis | Key Differentiating Features |
|---|---|
| Pseudogynaecomastia (lipomastia) | Soft, diffuse adipose without glandular tissue; common in obesity; no subareolar disc on pinch test |
| Male breast carcinoma | Hard, irregular, eccentric mass; usually unilateral; fixed to pectoralis; skin/nipple changes; older age |
| Ductal carcinoma in situ (DCIS) | Bloody nipple discharge; often detected incidentally on imaging |
| Breast abscess | Erythema, warmth, fluctuance, fever; post-traumatic or periductal mastitis |
| Lipoma | Soft, mobile, well-circumscribed; superficial to breast tissue |
| Sebaceous cyst | Punctum visible; superficial; not centred on areola |
Red-flag features mandating urgent imaging and surgical referral: Unilateral, hard, irregular or fixed mass; bloody nipple discharge; axillary lymphadenopathy; skin dimpling, retraction, or ulceration; rapid enlargement. Refer for mammography/ultrasound and biopsy within 2 weeks via rapid-access breast clinic.
Management
General Principles
Management of gynaecomastia depends on the underlying aetiology, duration, severity, symptom burden, and patient preference. Treatment aims to address reversible causes, relieve symptoms, and restore normal male breast contour when cosmetically or psychologically significant.
1
Identify and Treat Underlying Cause
Review medications (cessation/substitution), treat hyperthyroidism, manage liver/renal disease, address obesity. Allow 3โ6 months for spontaneous resolution after cause correction.
2
Physiological Gynaecomastia
Reassurance and observation. Pubertal gynaecomastia: review every 3โ6 months; 90% resolve by age 17. Surgical intervention rarely required (significant psychological distress persisting >2 years).
3
Medical Therapy (florid/early phase, <12 months)
Tamoxifen or testosterone replacement (for hypogonadism) as first-line agents. Dihydrotestosterone and clomiphene citrate as second-line options.
4
Surgical Intervention (fibrotic phase, >12 months, or failed medical therapy)
Liposuction (predominantly adipose), subcutaneous mastectomy (glandular tissue), or combined technique. Refer to plastic surgery.
Pharmacological Management
Tamoxifen
Nolvadex-Dยฎ ยท Generic ยท Selective oestrogen receptor modulator (SERM)
Adult dose
20 mg PO once daily for 3โ6 months; re-assess at 3 months; may extend to 12 months if partial response
Paediatric dose
0.2โ0.4 mg/kg/day PO; limited evidence; specialist supervision required. Use 10 mg daily in older adolescents.
Route
Oral
Renal adjustment
None required
Hepatic adjustment
Use with caution in severe hepatic impairment; monitor LFTs
Response rate
~80โ90% complete or partial response within 3โ6 months in florid-phase gynaecomastia
Side effects
Hot flushes, nausea, fatigue, visual disturbances (rare); thromboembolic risk
PBS status
Authority Required โ restricted to specialist-initiated treatment for gynaecomastia where surgery is inappropriate or deferred
Testosterone enantate
Primoteston Depotยฎ ยท Testosterone replacement
Adult dose
250 mg IM every 2โ3 weeks (loading: two injections at 2-week intervals, then maintenance every 3 weeks)
Paediatric dose
Not applicable for gynaecomastia
Route
Intramuscular
Renal adjustment
Use with caution; may worsen fluid retention in CKD
Hepatic adjustment
Avoid in severe hepatic impairment
Indication
Primary or secondary hypogonadism with confirmed low testosterone (<8 nmol/L morning)
PBS status
โ PBS General Benefit โ for diagnosed primary or secondary hypogonadism
Danazol
Danocrineยฎ ยท Synthetic androgen (attenuated)
Adult dose
200 mg PO once daily for 3โ6 months; limited to refractory cases
Route
Oral
Renal adjustment
Use with caution
Hepatic adjustment
Contraindicated in severe hepatic impairment; monitor LFTs fortnightly for 3 months
Response rate
~65โ80%; inferior to tamoxifen; more side effects
Side effects
Weight gain, oedema, acne, virilisation, hepatotoxicity, lipid abnormalities
PBS status
Authority Required โ endometriosis indication only; off-label use for gynaecomastia
Clomiphene citrate
Clomidยฎ ยท Selective oestrogen receptor modulator
Adult dose
50 mg PO once daily for 3โ6 months
Route
Oral
Mechanism
Stimulates hypothalamic GnRH โ โ LH/FSH โ โ endogenous testosterone production; anti-oestrogenic at breast
Response rate
~50โ70% partial or complete response; less evidence than tamoxifen
PBS status
Restricted Benefit โ for ovulation induction in females; off-label for gynaecomastia
First-line recommendation: For symptomatic, non-physiological gynaecomastia in the florid phase (<12 months), tamoxifen 20 mg daily for 3โ6 months has the strongest evidence base, with response rates of 80โ90% (Ting et al., 2000; Khan et al., 2009).
Surgical Management
Referral for surgical intervention is indicated in the following circumstances:
- Long-standing gynaecomastia (>12 months) with fibrotic tissue โ poor response to medical therapy expected
- Simon Grade III โ excess skin and tissue requiring resection
- Significant psychological distress or functional impairment
- Failure of or contraindication to medical therapy
Surgical techniques:
- Liposuction-assisted mastectomy: For mixed glandular-adipose tissue; small periareolar incision; most common approach for Grades IโIIb
- Subcutaneous mastectomy (open excision): For predominantly glandular tissue; inferior periareolar or trans-areolar incision
- Skin-reducing mastectomy: For Grade III with excess skin; may require free nipple grafting
Surgery may be funded through private health insurance or, in severe cases with documented psychological morbidity, may be considered under Medicare. Specialist plastic surgery or breast surgery referral is required.
Management of Specific Causes
| Cause | Management Approach |
|---|---|
| Spironolactone-induced | Switch to eplerenone 25โ50 mg daily if gynaecomastia intolerable. If not possible, add tamoxifen; continue spironolactone if cardiovascular benefit outweighs breast symptoms. |
| Primary hypogonadism | Testosterone replacement (Primoteston 250 mg IM q2โ3 wk or testosterone undecanoate 1000 mg IM q10โ14 wk). May take 3โ6 months for regression. |
| Klinefelter syndrome | Testosterone replacement from puberty onwards. Established gynaecomastia may require surgery. |
| Testicular tumour | Urology/oncology referral. Radical orchidectomy for confirmed malignancy; gynaecomastia regresses after successful treatment. |
| Hyperthyroidism | Treat hyperthyroidism (carbimazole, propylthiouracil, or radioiodine). Gynaecomastia typically resolves with euthyroid state. |
| Cirrhosis | Alcohol cessation, liver disease management. Testosterone replacement is generally avoided due to hepatotoxicity of oral formulations; transdermal route may be considered in specialist setting. |
Monitoring
- Repeat hormonal profile (testosterone, oestradiol, LH, FSH) at 3 months after initiating therapy
- Clinical assessment of breast tissue at 3-month intervals โ measure diameter of glandular tissue
- Monitor for tamoxifen side effects: LFTs at baseline and 6 monthly; visual symptoms review
- Testosterone monitoring: trough level before next injection; target 12โ25 nmol/L
- Psychological wellbeing assessment โ validated body image scales where indicated
- Surgical follow-up: standard post-operative review at 1 week, 6 weeks, 6 months; monitor for haematoma, seroma, contour deformity
Special Populations
Paediatrics
Pubertal gynaecomastia: Affects up to 60% of boys, peak onset 13โ14 years. Reassurance is first-line; 90% resolve by age 17. Investigation warranted only if bilateral tissue >4 cm, persisting >2 years, or associated with precocious puberty features.
Neonatal: Due to transplacental oestrogen; resolves within weeks. Do not manipulate tissue. Seek paediatric review if persistent discharge or progressive enlargement.
Tamoxifen:
Off-label in adolescents. 10 mg daily for 3โ6 months in severe pubertal gynaecomastia causing psychological distress โ specialist supervision only. Limited safety data.
Surgery: Reserved for persistent, severe, psychologically distressing gynaecomastia beyond age 16โ17; typically liposuction-assisted technique.
Elderly Men
Senescent gynaecomastia: Common in men >65 years; declining testosterone (โ1โ2% per year after age 30) and increased adipose aromatisation.
Drug review is essential: Higher polypharmacy burden. Common culprits: spironolactone, digoxin, proton pump inhibitors, antipsychotics, SSRIs.
Testosterone:
Consider cautiously. Benefits vs cardiovascular and prostate risks (TRAVERSE trial, 2023). Monitor PSA, haematocrit, and cardiovascular status. Endocrine Society guidelines recommend against routine use without clear hypogonadism (total testosterone <8 nmol/L on two occasions).
Male breast cancer risk increases with age: Lower threshold for mammography/biopsy in men >60 with new-onset unilateral mass.
Renal Impairment
CKD/dialysis: Gynaecomastia present in 15โ25% of men on haemodialysis. Driven by uraemic hypogonadism, altered SHBG, zinc deficiency, and medication use.
Zinc supplementation: Zinc deficiency is common in CKD. Supplementation (zinc sulfate 220 mg PO daily) may improve symptoms โ some evidence from small trials in dialysis patients.
Tamoxifen:
No dose adjustment required in renal impairment. Use as per standard regimen.
Testosterone:
Use cautiously in CKD; may worsen fluid retention. Avoid IM injections in severe CKD due to pain; consider transdermal formulations if available.
Hepatic Impairment
Cirrhosis: Gynaecomastia present in 30โ70% of men with alcoholic liver disease. Mechanism: impaired testosterone metabolism, increased peripheral aromatisation, elevated SHBG.
Alcohol cessation: Primary intervention. May allow resolution of gynaecomastia over 3โ6 months.
Danazol:
Contraindicated in severe hepatic impairment (hepatotoxicity risk).
Tamoxifen:
Use with caution; monitor LFTs. May be used in Child-Pugh AโB cirrhosis under specialist supervision.
Immunocompromised
HIV-related: Gynaecomastia reported in 2โ5% of men with HIV. Mechanism: antiretroviral therapy (particularly efavirenz), hypogonadism, immune reconstitution.
Antiretroviral switch: Consider switching from efavirenz to integrase inhibitor (e.g., dolutegravir) if gynaecomastia is a drug effect โ consultation with HIV specialist required.
Prostate cancer patients on antiandrogens: Bicalutamide-induced gynaecomastia affects 30โ70% of men. Prophylactic tamoxifen 20 mg daily or breast irradiation (single 12 Gy dose) reduces incidence. Discuss with treating oncologist.
Klinefelter & Intersex
Klinefelter syndrome (47,XXY): Most common genetic cause of primary hypogonadism (~1 in 600 males). Gynaecomastia present in 50โ70%. Karyotype analysis should be performed in all men with tall stature, small testes (<6 mL), and elevated gonadotrophins.
Management: Testosterone replacement from puberty; established gynaecomastia often requires surgical excision as fibrotic tissue is resistant to medical therapy.
Psychological support: Important for all DSD (differences of sex development) presentations. Multidisciplinary team including endocrinology, psychology, and surgical specialists.
Aboriginal and Torres Strait Islander Health Considerations
Aboriginal and Torres Strait Islander Health
๐ References
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