gynecomastia (redirected from Gynecomastia Etiology)

Gynecomastia 

Definition

Gyne refers to female, and mastia refers to the breast. Gynecomastia is strictly a male disease and is any growth of the adipose (fatty) and glandular tissue in a male breast. Not all breast growth in men is considered abnormal, just excess growth.

Causes and symptoms

Breast growth is directed exclusively by female hormones—estrogens. Although men have some estrogen in their system, it is usually insufficient to cause much breast enlargement because it is counterbalanced by male hormones—androgens. Upsetting the balance, either by more of one or less of the other, results in the male developing female characteristics, breast growth being foremost.

At birth both male and female infants will have little breast buds from their mother's hormones. These recede until adolescence, when girls always, and boys sometimes, have breast growth. At this time, the boy's breast growth is minimal, often one-sided and temporary.

Extra or altered sex chromosomes can produce intersex problems of several kinds. Breast growth along with male genital development is seen in Klinefelter syndrome—the condition of having an extra X (female) chromosome—and a few other chromosomal anomalies. One of the several glands that produce hormones can malfunction for reasons other than chromosomes. Failure of androgen production is as likely to produce gynecomastia as overabundant estrogen production. Testicular failure and castration can also be a cause. Some cancers and some benign tumors can make estrogens. Lung cancer is known to increase estrogens.

If the hormone manufacturing organs are functioning properly, problems can still arise elsewhere. The liver is the principle chemical factory in the body. Other organs like the thyroid and kidneys also effect chemical processes. If any of these organs are diseased, a chemical imbalance can result that alters the manufacturing process. Men with cirrhosis of the liver will often develop gynecomastia from increased production of estrogens.

Finally, drugs can also cause breast enlargement. Estrogens are given to men to treat prostate cancer and a few other diseases. Marijuana and heroin, along with some prescription drugs, have estrogen effects in some men. On the list are methyldopa (for blood pressure), cimetidine (for peptic ulcers), diazepam (Valium), antidepressants, and spironolactone (a diuretic).

Diagnosis

Carefully feeling the area beneath the nipple of an adolescent boy with breast enlargement will reveal a discreet and sometimes tender lump the size of a fat nickel or quarter. For more serious gynecomastia, the underlying disease will require evaluation, if it is not already well understood.

Key terms

Androgen — Male sex hormone.

Cirrhosis — Diffuse scarring caused by alcohol or chronic hepatitis often leading to liver failure.

Estrogen — Sex hormone responsible for stimulating female sexual characteristics.

Klinefelter syndrome — A condition in a male characterized by having an extra X (female) chromosome and suffering from infertility and gynecomastia.

Thyroid — A gland in the neck that makes thyroxin. Thyroxin regulates the speed of metabolism.

Treatment

This condition is usually not treated. If it is the result of endocrine disease, hormone manipulations may reduce the effects of the imbalance. There are a number of medical and surgical interventions possible. Radiation of misbehaving organs and cancers is considered an effective treatment.

Prognosis

The progress of gynecomastia is determined by its cause.

Resources

Books

Wilson, Jean D. "Endocrine Disorders of the Breast." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.

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gynecomastia /gyne·co·mas·tia/ (-ko-mas´te-ah) excessive development of the male mammary glands, even to the functional state.

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gyn·e·co·mas·ti·a (gn-k-mst-, jn-)

n.

Abnormal enlargement of the male mammary glands, sometimes to the point of secreting milk.

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gynecomastia

[gī′nəkōmas′tē·ə, jī′-, jin′-]

Etymology: Gk, gyne + mastos, breast

an abnormal enlargement of one or both breasts in males. Milk production may or may not be present. The condition is usually temporary and benign. It may be caused by hormonal imbalance; a tumor of an adrenal gland, testis, or pituitary; use of medication that contains estrogens or steroidal compounds; or failure of the liver to inactivate circulating estrogen, as in alcoholic cirrhosis. Less commonly the gynecomastia may be caused by a hormone-secreting tumor of the breast, lung, or other organ. It tends to subside spontaneously but, if marked, may be corrected surgically for cosmetic or psychologic reasons. Biopsy may be performed to rule out cancer. Also spelled gynaecomastia. Also called gynecomasty.

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gynecomastia

abnormal enlargement of the mammary glands in the male, even to the point of secreting milk; usually the result of endocrine influences such as in the feminizing syndrome associated with functional Sertoli cell tumors of the testes.

Gynecomastia of a buck goat. By permissionfrom Buergelt CD, Color Atlas of Reproductive Pathology ofDomestic Animal, Mosby, 1996

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gynecomastia

Benign enlargement of ♂ breast that most commonly affects boys and adolescents, often regresses at puberty; it is usually due to a proliferation of glandular component; may occur in Klinefelter syndrome or after malnutrition Age-related peaks 1. Perinatal, in 60-90% of ♂ at birth, due to transplacental passage of estrogens 2. Pubertal, up to 70%, depending on stringency of definition 3. Involutional, age 50-80% Treatment Clomiphene, tamoxifen, testolactone, surgery. See Adolescent gynecomastia.

Gynecomastia Etiology

Endocrinopathy Orchitis, hypogonadism–androgen deficiency, androgen resistance, tumors/hyperplasia of adrenal gland, testes, eg Leydig cell tumor–↑ hCG, lung CA, Klinefelter syndrome–↑ risk of breast CA and thyroid hyperplasia

Drugs α-methyldopa, amphetamine, androgens, benzodiazepines, cimetidine, chemotherapeutics, digitalis, INH, marijuana, penicillamine, phenothiazine, reserpine, spironolactone, tricyclic antidepressants

Other conditions Starvation diet–mechanism: testicular, hepatic hypofunction or on resuming feeding, hemodialysis, liver disease–cirrhosis, hepatomas, hemochromatosis, due to ↓ hepatic metabolism of estrogens, mycosis fungoides, myotonic dystrophy with spastic paraplegia, leprosy