Gynecomastia is enlargement of the gland tissue of the male breast. During infancy, puberty, and in middle-aged to older men, gynecomastia can be common.
Gynecomastia must be distinguished from pseudogynecomastia, which refers to the presence of fat deposits in the breast area of obese men.
True gynecomastia results from growth of the glandular, or breast tissue, which is present in very small amounts in men.
The primary symptom of gynecomastia is enlargement of the male breasts. As mentioned before, gynecomastia is the enlargement of glandular tissue rather than fatty tissue. It is typically symmetrical in location with regard to the nipple and may have a rubbery or firm feel.
Gynecomastia usually occurs on both sides but can be unilateral in some cases. The enlargement may be greater on one side even if both sides are involved. Tenderness and sensitivity may be present, although there is typically no severe pain.
The most important distinction with gynecomastia is differentiation from male breast cancer, which accounts for about 1% of overall cases of breast cancer. Cancer is usually confined to one side, is not necessarily centered around the nipple, feels hard or firm, and can be associated with dimpling of the skin, retraction of the nipple, nipple discharge, and enlargement of the underarm (axillary) lymph nodes.
Gynecomastia results from an imbalance in hormone levels in which levels of estrogen (female hormones) are increased relative to levels of androgens (male hormones). Gynecomastia that occurs in normally-growing infantand pubertal boys that resolves on its own with time is known as physiologic gynecomastia.
All individuals, whether male or female, possess both female hormones (estrogens) and male hormones (androgens). During puberty, levels of these hormones may fluctuate and rise at different levels, resulting in a temporary state in which estrogen concentration is relatively high.
Studies regarding the prevalence of gynecomastia in normal adolescents have yielded widely varying results, with prevalence estimates as low as 4% and as high as 69% of adolescent boys. These differences probably result from variations in what is perceived to be normal and the different ages of boys examined in the studies.
Gynecomastia caused by transient changes in hormone levels with growth usually disappears on its own within six months to two years. Occasionally, gynecomastia that develops in puberty persists beyond two years and is referred to as persistent pubertal gynecomastia.
Gynecomastia, especially in pubertal males, often goes away on its own within about six months, so observation is preferred over specific treatment in many cases. Stopping any offending medications and treatment of underlying medical conditions that cause gynecomastia are also mainstays of treatment.
Treatments are also available to specifically address the problem of gynecomastia, but data on their effectiveness are limited, and no drugs have yet been approved by the U.S. Food and Drug Administration (FDA) for treatment of gynecomastia. Medications are more effective in reducing gynecomastia in the early stages, since scarring often occurs after about 12 months. After the tissue has become scarred, medications are not likely to be effective, and surgical removal is the only possible treatment.
Medications that have been used to treat gynecomastia include:
- Testosterone replacement has been effective in older men with low levels of testosterone, but it is not effective for me who have normal levels of the male hormone.
- The selective estrogen receptor modulators (SERMs) tamoxifen (Nolvadex) and raloxifene (Evista) have been shown to reduce breast volume in gynecomastia, although they are not able to entirely eliminate all the breast tissue. This type of therapy is most often used for severe or painful gynecomastia.
- Aromatase inhibitors [such as anastrozole (Arimidex)] are a class of medication that interferes with the synthesis of estrogen. While these drugs theoretically should be able to reduce breast mass in gynecomastia, studies have failed to show a significant benefit in treating gynecomastia.