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Gynaecomastia (British English) or gynecomastia (American English) is the development of abnormally large breasts on men. The term comes from the Ancient Greek gynaeca meaning “woman” and mastos meaning “breast”. The condition can occur physiologically in neonates, in adolescents, and in the elderly. In adolescent boys, 90% of such cases the symptoms disappear in a matter of months to a few years at most. It is generally a result of an imbalance in hormones, although there are many different root causes. Gynecomastia is not simply a buildup of adipose tissue, but includes the development of glandular tissue as well.


Physiologic gynecomastia occurs in neonates, at puberty and with aging.

Potential pathologic causes of gynecomastia are: medications including hormones, increased serum estrogen, decreased testosterone production, androgen receptor defects, chronic kidney disease, chronic liver disease, HIV, and other chronic illness. Gynecomastia as a result of spinal cord injury and refeeding after starvation has been reported. In 25% of cases, the cause of the gynecomastia is not known.

Medications cause 10-20% of cases of gynecomastia. These include cimetidine, omeprazole, spironolactone, finasteride and certain antipsychotics. Some act directly on the breast tissue, while other lead to increased secretion of prolactin from the pituitary by blocking the actions of dopamine (prolactin-inhibiting factor/PIF) on the lactotrope cell groups in that organ. Androstenedione, used as a performance enhancing food supplement, can lead to breast enlargement by excess estrogen activity. Marijuana use is also thought by some to be a possible cause, but this is controversial.

Increased estrogen levels can also occur in certain testicular tumors, and in hyperthyroidism. Certain adrenal tumors cause elevated levels of androstenedione which is converted by the enzyme aromatase into estrone, a form of estrogen. Other tumors that secrete hCG can increase estrogen. A decrease in estrogen clearance can occur in liver disease, and this may be the mechanism of gynecomastia in liver cirrhosis. Obesity tends to increase estrogen levels.

Decreased testosterone production can occur in congenital or acquired testicular failure, for example in genetic disorders such as Klinefelter Syndrome. Diseases of the hypothalamus or pituitary can also lead to low testosterone. Abuse of anabolic steroids has a similar effect.

Although stopping these medications can lead to regression of the gynecomastia, surgery is sometimes necessary to eliminate the condition.


The condition usually can be diagnosed by examination by a physician. Occasionally, imaging by X-rays or ultrasound is needed to confirm the diagnosis. Blood tests are required to see if there is any underlying disease causing the gynecomastia.


Gynecomastia is not physically harmful, but in some cases can be an indicator of other more dangerous underlying conditions. Furthermore, it can frequently present social and psychological difficulties for the sufferer. Weight loss can alter the condition in cases where it is triggered by obesity, but for many it will not eliminate it as the breast tissue remains.


Treating the underlying cause of the gynecomastia may lead to improvement in the condition. Patients should stop taking medications which can cause gynecomastia. Anti-estrogen medications, such as tamoxifen and clomiphene or androgens can be used. Aromatase inhibitors are another treatment option, although they are not universally approved for the treatment of gynecomastia. Endocrinological attention may help during the first 2-3 years. After that window, however, the breast tissue tends to remain and harden, leaving surgery (either liposuction or reduction mammoplasty) the only treatment option. Radiation therapy is sometimes used to prevent gynecomastia in patients with prostate cancer prior to estrogen therapy. There are people who choose to live with the condition and use a bra as an option for treatment.


  • Glass AR. Gynecomastia. Endocrinol Metab Clin North Am. 1994 Dec; 23(4):825-37. PMID 7705322
  • Braunstein GD. Aromatase and Gynecomastia. Endocr Relat Cancer. 1999 Jun;6(2):315-24. PMID 10731125
  • Braunstein GD. Gynecomastia. N Engl J Med. 1993 Feb 18;328(7):490-5. PMID 8421478
  • Peyriere H, et al. Report of gynecomastia in five male patients during antiretroviral therapy for HIV infection. AIDS. 1999 Oct 22;13(15):2167-9. PMID 10546872
  • Heruti RJ, et al. Gynecomastia following spinal cord disorder. Arch Phys Med Rehabil. 1997 May;78(5):534-7. PMID 9161376

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