Gynecomastia is the breast enlargement in males due to increased mammary glandular proliferation. It is caused by an increase in the ratio of estrogen to androgen activity. It is common and physiological in neonates, pubertal boys, and elderly persons. Some cases are pathological and secondary to drugs, chronic liver, kidney disease, or hyperthyroidism. The majority are asymptomatic and do not need treatment.

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adolescent with gynecomastia

Image: “Adolescent with gynecomastia.” by David Andrew Copeland, Dr. Mordcai Blau – Own work. License: CC BY-SA 3.0


Gynecomastia is classified into 3 major groups: physiological, pathological, and idiopathic:

Physiological gynecomastia

  • Neonates 
    • Due to elevated estrogen concentrations in fetal blood
    • Typically regresses by the age of 3 weeks of life
  • Pubertal boys 
    • Due to a transient increase in estradiol concentration at the onset of puberty
    • Typically regresses after 18 months of puberty
    • Occurs in 50% of male teenagers
    • Not common after the age of 17 years
  • Senile
    • Due to increased body fat content which is responsible for the increased conversion of androgens to estrogens

Pathological gynecomastia

  • Medications: efavirenz, omeprazole, HIV nucleoside reverse transcriptase inhibitors, opiates, ketoconazole, ranitidine, spironolactone, tricyclic antidepressants, phenytoin
  • Metabolic disorders: liver disease, cirrhosis, type 1 diabetes, hyperthyroidism, chronic renal disease
  • Hypogonadism: Klinefelter syndrome
  • Testicular tumors: Leydig and Sertoli cell tumors

Idiopathic gynecomastia

  • Cannot be linked to a specific etiology.
  • 25% of cases of gynecomastia are idiopathic.

Video Gallery

Gynecomastia by Carlo Raj, MD
Gynecomastia in Adolescent Males by Brian Alverson, MD


To recall the causes of gynecomastia, remember CODES:

  • Cirrhosis
  • Obesity
  • Digoxin
  • Estrogen
  • Spironolactone

Clinical Presentation

Most patients are asymptomatic.

  • Clinical features:
    • Concentric with the nipple, bilateral, and firm
    • Can present with tender areolar complex
  • Clinical history:
    • Family history of gynecomastia
    • Age of onset and duration of the condition
    • History of mumps, testicular trauma, alcohol use, or drug use
    • Any recent changes in nipple size and any pain or discharge from the nipples
    • History of sexual dysfunction, infertility, or hypogonadism
  • Consider malignancy if:
    • Unilateral, ulcerative, not concentric with nipple
    • Associated with bloody discharge or axillary lymphadenopathy


  • Diagnosis is made via relevant history and physical examination:
    • History: age, family history, drug use, medication use, progression, etc.
    • Physical exam: palpable mass of tissue at least 0.5 cm in diameter usually underlying the nipple
  • Laboratory
    • Serum levels of testosterone, estradiol, luteinizing hormone, and hCG can be used to identify pathological causes.
    • Luteinizing hormone and follicle-stimulating hormone levels can be checked to exclude hypogonadism.
    • Liver function tests, renal function tests, and thyroid hormone assay can be used to identify reversible or treatable causes of gynecomastia.
  • Imaging:
    • Mammography and breast ultrasonography with biopsy: in case of suspicion of breast cancer
    • Testicular ultrasound: might be indicated to exclude testicular tumors
    • Abdominal computed tomography scans or ultrasonography: used to exclude liver tumors and/or liver cirrhosis
adolescent with gynecomastia

Image: “Adolescent with gynecomastia.” by David Andrew Copeland, Dr. Mordcai Blau – Own work. License: CC BY-SA 3.0


  • Treat the underlying cause
    • Discontinue the offending drug
    • Treat the underlying medical condition
  • Observation
    • Indicated in physiological gynecomastia throughout age period
    • Indicated in pathological gynecomastia < 6 months of onset
  • Medical therapy
    • Testosterone replacement: in patients with hypogonadism
    • Selective estrogen receptor modulators (e.g., tamoxifen): for severe physiological gynecomastia or idiopathic gynecomastia lasting longer than 3 months
  • Surgery: subcutaneous mastectomy is indicated for cosmesis in gynecomastia lasting for longer than 1 year

Differential Diagnoses

  • Hypogonadism: condition characterized by decreased sex steroid production in the gonads. In men, this can be the result of primary testicular failure or secondary testicular failure due to pituitary or hypothalamic disorders.
  • Breast cancer: malignancy that originates in breast tissue in which 1% of cases are men. Explore this diagnosis if the gynecomastia is unilateral, ulcerative, not concentric with the nipple, associated with bloody discharge, or axillary lymphadenopathy is present.
  • Mastitis: the inflammation of the mammary gland tissue, which can be lactational or non-lactational. Mostly affects women in childbearing age within the first 6 weeks of lactation.
  • Lipoma: a benign soft tissue tumor that is composed of mature adipocytes. It usually presents as a subcutaneous, soft mass that is mobile and painless.
  • Pseudogynecomastia: male breast area has excess adipose (fat) tissue behind, around and under the nipples. It is usually due to obesity.
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