Gynecomastia is a condition in which the breasts become enlarged in boys or men, sometimes causing discomfort or nipple tenderness. It is usually the result of a hormonal imbalance and typically occurs during infancy, adolescence, or mid- to late-life. The condition often goes away on its own, but treatments are available for severe or persistent cases. When gynecomastia is the result of an underlying health problem, treatment of that problem usually improves the gynecomastia as well.
Up to 70 percent of boys in early to mid-puberty experience gynecomastia because of the normal hormonal changes that occur during puberty. Gynecomastia is also common among middle-aged and elderly men. In this population, up to 65 percent of men are affected.
COMMON CAUSES OF GYNECOMASTIA
Although people tend to think of androgens as "male hormones" and estrogens as "female hormones," people of both sexes produce both types of hormones. In males, androgens are by far the predominant hormone, but small amounts of estrogen are also present. Gynecomastia can happen when the balance shifts, with an increase in estrogen or decrease in androgens. This can occur because of expected hormonal changes during puberty or aging, or because of the use of certain drugs or herbal products.
The most common causes of gynecomastia in adult men include:
- Pubertal gynecomastia that does not resolve — 25 percent
- Drugs — 10 to 25 percent
- Unknown causes (idiopathic) — 25 percent
Puberty — Gynecomastia that occurs during puberty usually resolves without treatment within six months to two years. The condition sometimes develops between ages 10 and 12 years, and most commonly occurs between ages 13 and 14. It is uncommon for the condition to persist beyond age 17.
Drugs — Many drugs have been associated with gynecomastia, including:
- Spironolactone (Aldactone), a drug used to treat heart failure, high blood pressure, and several other conditions.
- Ketoconazole, a drug used to treat fungal infections.
- Cimetidine (Tagamet), ranitidine (Zantac), and related drugs called H2-receptor blockers. These drugs are used to treat stomach ulcers and severe heartburn.
If gynecomastia is caused by one of the drugs you take, your healthcare provider may recommend that you stop using the drug or replace it with another drug that is less likely to cause the condition.
Gynecomastia occurs in up to 75 percent of men who take drugs called antiandrogens to treat prostate cancer. While these men may not be able to stop or substitute their prostate cancer treatment, they may be able to take steps to prevent gynecomastia. (See 'Prostate cancer patients' below.)
Herbal products — Gynecomastia in children has been associated with regular use of skin care products (lotions, soaps, and shampoos) containing tea tree oil and lavender oil . These oils contain plant estrogens and can affect the body's hormone balance. Gynecomastia usually resolves completely after stopping the products. Soy products, such as soy milk, do not usually cause gynecomastia unless a large quantity is consumed.
Treatment for HIV/AIDS (HAART) — Men taking combination treatment for HIV/AIDS, called highly active antiretroviral therapy (HAART), sometimes develop enlarged breasts. In most cases, this breast enlargement is due to fat redistribution, which is a side effect of the treatment. In some cases, though, true gynecomastia has been associated with HAART.
Unknown causes (idiopathic) — It is not always clear what causes gynecomastia during mid- to late-life. Still, as men age, blood testosterone levels decline and the hormone balance changes, favoring an increased level of estrogen. These factors probably conspire to account for most cases of "idiopathic" gynecomastia.
Gynecomastia should not be confused with pseudogynecomastia, which occurs in overweight men whose breasts enlarge because of fat deposits.
If you are a man or boy with enlarged or tender breasts, your healthcare provider will perform an examination to determine whether the tissue in your breasts is fatty or glandular. Glandular tissue is designed to secrete substances, such as milk or hormones, and usually has a network of ducts that can be felt.
If the provider has difficulty determining whether you have gynecomastia, he or she may recommend that you have a mammogram, a specialized x-ray of the breast.
Laboratory tests — In certain situations, blood tests may be ordered to measure the level of hormones. Blood tests are not usually needed if the cause of the gynecomastia (eg, puberty, drugs) is known.
The best treatment for gynecomastia depends upon its cause, duration, and severity, and whether it causes pain or discomfort.
Adolescents — Because pubertal gynecomastia usually goes away on its own, treatment is not usually recommended initially. Instead, the provider will keep close tabs on the condition for several months. In most cases, pubertal gynecomastia resolves during that time.
For boys with severe gynecomastia that is causing substantial tenderness or embarrassment, a short course of a drug called tamoxifen (Nolvadex) or raloxifene (Evista) may be recommended. These drugs block the effects of estrogen in the body and can reduce the size of the breasts somewhat. However, neither of these drugs is approved in the United States for the treatment of gynecomastia. Drugs may be prescribed without FDA approval, although the risks and benefits have not been studied completely.
Adult men — Treatment is also usually delayed in adult men whose gynecomastia is likely to be caused by an underlying health problem or by drugs. In these men, treating the underlying condition or suspending the problematic drug usually allows the gynecomastia to resolve.
For men with idiopathic gynecomastia that causes discomfort and lasts more than three months, a short course of tamoxifen or raloxifene may be recommended.
Prostate cancer patients — Gynecomastia is a known complication of a treatment for prostate cancer (called antiandrogen monotherapy). Approximately 75 percent of men who use this treatment develop gynecomastia. However, there are several treatment options available to prevent the development of gynecomastia, including tamoxifen and radiation therapy. (See "Patient information: Treatment for advanced prostate cancer (Beyond the Basics)".)
Tamoxifen — Tamoxifen can be taken along with the anti-cancer (antiandrogen) treatment. Tamoxifen must be taken every day for the duration of antiandrogen treatment. In one study, only 8 percent of men who took tamoxifen plus an antiandrogen developed gynecomastia (compared with 68 percent of men who took the antiandrogen alone) .
Tamoxifen may also be given to men who develop gynecomastia while taking antiandrogens.
Radiation therapy — Treating the breasts with radiation before antiandrogen treatment begins can prevent gynecomastia. Radiation treatment (RT) is usually delivered in one to three sessions (similar to having an x-ray). In the study above, 34 percent of men who had RT before antiandrogen therapy developed gynecomastia .
Gynecomastia that has already developed can be treated with higher radiation doses and may improve pain. However, when given after breasts have already developed, radiation is not very effective at reducing breast size.
Radiation therapy versus tamoxifen — Although tamoxifen may be more effective than radiation for men who take antiandrogen monotherapy, tamoxifen needs to be taken for the duration of antiandrogen therapy. For some men, taking another medication every day is less convenient than to have three sessions of radiation therapy.
Surgery — Although tamoxifen and raloxifene are effective for men and boys who have had enlarged breasts for a few months, the drug is not effective in men who have had the condition for one to two years or more. For these men, surgery is an option to reduce the size of the breasts. For adolescents, surgery is generally not recommended until puberty is completed; there may be regrowth of the breast tissue if the surgery is performed before puberty is completed.
The extent of surgery depends upon the severity of the breast enlargement and whether there is also excess fatty tissue. Many men are treated with a combination of surgical removal of the glandular tissue and liposuction.
More extensive cosmetic surgery, including partial surgical removal of the breast skin, is required for men with more severe breast enlargement or those who have excessive sagging of the breast tissue, which may occur after weight loss.
- Gynecomastia in adolescent boys is usually caused by puberty-related hormonal changes and typically resolves on its own. In extreme or painful cases, a brief course of tamoxifen may be recommended.
- Gynecomastia in adult men is usually caused by another underlying health problem or by the use of a drug. In such cases, treating the underlying condition or suspending the drug usually allows gynecomastia to resolve. When the cause of gynecomastia cannot be identified, brief use of tamoxifen may be recommended.
- Men who have had gynecomastia for more than one year do not typically benefit from the use of tamoxifen. For them, surgery to reduce the size of the breasts is an option.
- Men with prostate cancer who undergo certain types of hormone treatment (eg, antiandrogen monotherapy) are at risk for developing gynecomastia. Pre-treatment with radiation or taking a medication (tamoxifen) along with the antiandrogen are two options for preventing breast growth.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: When men develop breasts (gynecomastia) (The Basics)
Patient information: Androgen replacement in men (The Basics)
Patient information: Low testosterone in men (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Treatment for advanced prostate cancer (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Causes and evaluation of gynecomastia
Epidemiology and pathogenesis of gynecomastia
Management of gynecomastia
Side effects of androgen deprivation therapy
The following organizations also provide reliable health information.
- National Library of Medicine
(www.nlm.nih.gov/MEDLINEPLUS/ency/article/003165.htm, also available in Spanish)
- American Society of Plastic Surgeons