Gynecomastia is a condition of overdevelopment or enlargement of the breast tissue in children and adults who have a penis. The breasts become larger. They may grow unevenly.

Gynecomastia often happens when a preteen or teenage child is going through the hormonal changes of puberty. But it can also happen to newborn babies and to adults as they age.

Gynecomastia is usually a benign (noncancerous) condition. It may be linked to many different causes of hormone changes. In many cases, the cause isn't known.

Gynecomastia is often caused by changes in levels of the hormones estrogen and testosterone. But it can be caused by other things as well.

Gynecomastia can be a side effect of certain medicines, such as antidepressants, antibiotics, chemotherapy, prostate cancer medicines, or ulcer or cardiovascular medicines. Illegal drugs, such as anabolic steroids, heroin, or marijuana can also cause gynecomastia.

Some diseases and health conditions may also cause gynecomastia. These include:

• Liver diseases
• Kidney disease
• Lung cancer
• Testicular cancer
• Tumors of the adrenal glands or pituitary gland
• Some conditions that a baby is born with (congenital disorders)
• Thyroid disorders
• Injury
• Obesity

Newborn babies may have a short-term form of gynecomastia. This is often because the birth parent's estrogen stays in a baby's blood for a while after birth.

Gynecomastia is not linked to breast cancer. It's rare that people with a penis get breast cancer. But your doctor may do some tests and examine you to rule out breast cancer.

You may have gynecomastia in one or both breasts. It may start as a lump or fatty tissue beneath the nipple, which may be sore. The breasts often get larger unevenly.

The symptoms of gynecomastia may look like other health conditions or problems. Always see your doctor for a diagnosis.

Your doctor will take your past health and medicine history and give you a physical exam.

To rule out other diseases or conditions, you may also have tests, including:

• Blood tests, including liver function tests and hormone studies
• Urine tests
• A low-dose X-ray of your breast (mammogram)
• A small breast tissue sample (a biopsy) may be removed and checked for cancer cells

In some cases, tests are not needed to diagnose the condition.

Your doctor may suggest that you see a doctor (endocrinologist) who specializes in hormones and how they affect many organs.

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

Most cases of gynecomastia happen during puberty. The condition usually gets better on its own without treatment. This may take from 6 months to 2 or 3 years.

If a medicine is causing your breast enlargement, you may need to stop taking the medicine. That can solve the problem. If a disease is causing the condition, the disease will need to be treated. If these problems are not addressed, the condition can come back after it is treated.

Hormone therapy may be used to treat gynecomastia.

In rare cases, surgery may be used to remove the extra tissue.

• Gynecomastia is an overdevelopment or enlargement of the breast tissue in children and adults who have a penis.
• The breasts become larger. They often grow unevenly.
• It's often caused by changes in levels of the hormones estrogen and testosterone. Other things may cause it as well.
• Most cases happen when a preteen or teenage child is going through puberty. But it can also happen to newborn babies and older adults.
• It often goes away on its own. In some cases, hormone therapy is needed. Surgery may also help treat the condition.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are and when they should be reported.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours and on weekends and holidays.