What is "gynecomastia"

1881, from Greek gyne (see queen) + mazos "breast," variant of mastos (see masto-) + abstract noun ending -ia.

n. (context American spelling medicine English) Excessive development of breasts in males, resembling the breast development in women.

n. excessive development of the breasts in males; usually the result of hormonal imbalance or treatment with certain drugs (including some antihypertensives)

Gynecomastia is a common disorder of the endocrine system in which there is a non-cancerous increase in the size of male breast tissue. Most adolescent boys, up to 70%, have some breast development during puberty. Newborn and adolescent males often experience temporary gynecomastia due to the influence of maternal hormones and hormonal changes during puberty, respectively.

The development of gynecomastia is usually associated with benign pubertal changes; in adolescent boys, the condition is often a source of psychological distress. However, 75% of pubertal gynecomastia cases resolve within two years of onset without treatment. In rare cases, gynecomastia has been known to occur in association with certain disease states. Gynecomastia may be seen in individuals with Klinefelter syndrome or certain cancers, with disorders involving the endocrine system or metabolic dysfunction, with the use of certain medications, or in older males due to a natural decline in testosterone production.

Disturbances in the endocrine system that lead to an increase in the ratio of estrogens/ androgens are thought to be responsible for the development of gynecomastia. This may occur even if the levels of estrogens and androgens are both appropriate but the ratio is altered. The disorder is usually diagnosed by a physician after a detailed history and physical examination. Conservative management of gynecomastia is often appropriate as the condition commonly resolves on its own. Medical treatment of gynecomastia that has persisted beyond two years is often ineffective. Medications such as aromatase inhibitors have been found to be effective in rare cases of gynecomastia from disorders such as aromatase excess syndrome or Peutz–Jeghers syndrome, but surgical removal of the excess tissue is usually required.