Gynecomastia (guy-nuh-koh-MAS-tee-uh) is an increase in the amount of breast gland tissue in boys or men, caused by an imbalance of the hormones estrogen and testosterone. Gynecomastia can affect one or both breasts, sometimes unevenly.

Pseudogynecomastia refers to an increase in fat but not glandular tissue in male breasts.

Newborns, boys going through puberty and older men may develop gynecomastia as a result of normal changes in hormone levels, though other causes also exist.

Generally, gynecomastia isn't a serious problem, but it can be tough to cope with the condition. Men and boys with gynecomastia sometimes have pain in their breasts and may feel embarrassed.

Gynecomastia may go away on its own. If it persists, medication or surgery may help.

Most adult men with gynecomastia report no symptoms. Signs and symptoms of the condition may include:

• Pain, particularly in adolescents
• Swollen breast tissue
• Breast tenderness
• Nipple sensitivity with rubbing against clothes

When to see a doctor

See your doctor if you have:

• Swelling
• Pain or tenderness
• Nipple discharge in one or both breasts

Gynecomastia is triggered by a decrease in the amount of the hormone testosterone compared with estrogen. The decrease can be caused by conditions that block the effects of testosterone, reduce testosterone or increase your estrogen level.

Several things can upset the hormone balance, including the following.

Natural hormone changes

The hormones testosterone and estrogen control sex characteristics in both men and women. Testosterone controls male traits, such as muscle mass and body hair. Estrogen controls female traits, including the growth of breasts.

Most people think of estrogen as an exclusively female hormone, but men also produce it — though usually in small quantities. Male estrogen levels that are too high or are out of balance with testosterone levels can cause gynecomastia.

• Gynecomastia in infants. More than half of male infants are born with enlarged breasts due to the effects of their mother's estrogen. Generally, the swollen breast tissue goes away within two to three weeks after birth.
• Gynecomastia during puberty. Gynecomastia caused by hormone changes during puberty is relatively common. In most cases, the swollen breast tissue will go away without treatment within six months to two years.
• Gynecomastia in adults. Researchers have estimated that the prevalence among men ages 50 to 80 is between 24% and 65%. However, most men with the condition experience no symptoms.

Medications

A number of medications can cause gynecomastia. These include:

• Anti-androgens used to treat an enlarged prostate, prostate cancer and other conditions. Examples include flutamide, finasteride (Proscar, Propecia) and spironolactone (Aldactone, Carospir).
• Anabolic steroids and androgens to treat hormone deficiencies, delayed puberty, or muscle loss from another disease.
• AIDS medications. The estrogen-like properties of some HIV medications can cause gynecomastia, especially Efavirenz (Sustiva).
• ADHD medications that contain amphetamines, such as Adderall.
• Anti-anxiety medications, such as diazepam (Valium).
• Tricyclic antidepressants.
• Antibiotics.
• Ulcer medications, such as the over-the-counter drug cimetidine (Tagamet HB).
• Chemotherapy to treat cancer.
• Heart medications, such as digoxin (Lanoxin) and calcium channel blockers.
• Stomach-emptying medications, such as metoclopramide (Reglan).

Recreational drugs, illicit drugs and alcohol

Substances that can cause gynecomastia include:

• Alcohol
• Anabolic steroids used to build muscle and enhance athletic performance
• Amphetamines
• Marijuana
• Heroin
• Methadone (Methadose)

Health conditions

Several health conditions can cause gynecomastia by affecting the balance of hormones. These include:

• Hypogonadism. Conditions that lower testosterone production, such as Klinefelter syndrome or pituitary insufficiency, can be associated with gynecomastia.
• Aging. Hormone changes that occur with aging can cause gynecomastia, especially in men who are overweight.
• Tumors. Some tumors, such as those involving the testes, adrenal glands or pituitary gland, can produce hormones that alter the male-female hormone balance.
• Hyperthyroidism. In this condition, the thyroid gland produces too much of the hormone thyroxine.
• Kidney failure. About half the people being treated with dialysis experience gynecomastia due to hormonal changes.
• Liver failure and cirrhosis. Changes in hormone levels related to liver problems and cirrhosis medications are associated with gynecomastia.
• Malnutrition and starvation. When your body is deprived of adequate nutrition, testosterone levels drop while estrogen levels remain the same, causing a hormonal imbalance. Gynecomastia can also happen when normal nutrition resumes.

Herbal products

Plant oils, such as tea tree or lavender, used in shampoos, soaps or lotions have been associated with gynecomastia. This is probably due to their weak estrogenic activity.

Risk factors for gynecomastia include:

• Adolescence
• Older age
• Use of anabolic steroids to enhance athletic performance
• Certain health conditions, including liver and kidney disease, thyroid disease, hormonally active tumors, and Klinefelter syndrome

Gynecomastia has few physical complications, but it can cause psychological or emotional problems caused by appearance.

There are a few factors you can control that may reduce the risk of gynecomastia:

• Don't use drugs. Examples include anabolic steroids, amphetamines, heroin and marijuana.
• Avoid alcohol. Don't drink alcohol. If you do drink, do so in moderation.

A diagnosis of gynecomastia is based on a review of your symptoms and a medical exam that includes a careful evaluation of your breast tissue, abdomen and genitals.

Tests

Your doctor will likely order tests to identify a possible cause of gynecomastia, to screen for possible breast cancer and to rule out other conditions. These may include:

• Blood tests
• Mammograms
• Computerized tomography (CT) scans
• Magnetic resonance imaging (MRI) scans
• Testicular ultrasounds
• Tissue biopsies

Conditions that cause similar symptoms

Your doctor will want to be sure that your breast swelling is gynecomastia and not another condition. Other conditions that can cause similar symptoms include:

• Fatty breast tissue (pseudogynecomastia). Some men and boys, especially those with obesity, have breast fat that resembles gynecomastia. This isn't the same as gynecomastia and doesn't need additional evaluation.
• Breast cancer. Breast cancer is uncommon in men but can occur. Enlargement of one breast or the presence of a firm nodule raises the concern for male breast cancer.
• A breast abscess. This is an infection of the breast tissue.

Most cases of gynecomastia resolve over time without treatment. However, if gynecomastia is caused by an underlying condition — such as hypogonadism, malnutrition or cirrhosis — that underlying condition may need treatment.

If you're taking medications that may be the cause of gynecomastia, your doctor may recommend stopping them or substituting another medication.

In adolescents with no apparent cause of gynecomastia other than normal hormone changes during puberty, the doctor may recommend periodic reevaluations every three to six months to see if the condition improves on its own. Gynecomastia in adolescents often goes away without treatment in less than two years.

Treatment may be necessary if gynecomastia doesn't improve on its own or if it causes significant pain, tenderness or embarrassment.

Medications

Medications used to treat breast cancer and other conditions may be helpful for some men with gynecomastia. They include:

• Tamoxifen (Soltamox)
• Aromatase inhibitors, such as anastrozole (Arimidex)

Although these medications are approved by the Food and Drug Administration, they have not been approved specifically for use in people with gynecomastia.

Surgery to remove excess breast tissue

If enlarged breasts are significant and bothersome even after initial treatment or observation, your doctor may advise surgery.

Two gynecomastia surgery options are:

• Liposuction. This surgery removes breast fat but not the breast gland tissue itself.
• Mastectomy. This type of surgery removes the breast gland tissue. The surgery is often done using only small incisions. This less invasive type of surgery involves less recovery time.

For men, enlarged breasts can be stressful and embarrassing. Gynecomastia can be difficult to hide and a challenge to romantic relationships. During puberty, gynecomastia can make boys a target for teasing from peers. It can make activities such as swimming or changing in the locker room traumatic.

Whatever your age, you may feel like your body has betrayed you and you may feel unhappy with yourself. These feelings are normal, but to help you cope you can:

• Get counseling. Talk therapy can help you avoid anxiety and depression caused by gynecomastia. It can also help you communicate with your partner or family members so that they understand what you're going through.
• Reach out to your family and friends. You may feel embarrassed to talk about gynecomastia with the people you care about. But explaining your situation and asking for support will likely strengthen your relationships and reduce stress.
• Connect with others who have gynecomastia. Talking with men who have had a similar experience can help you cope. Websites such as Gynecomastia.org provide a forum for connecting with others who have the condition.