Gynecomastia is a condition wherein glandular tissue excessively develops in males. It can be distinguished by the presence of a rubbery and firm mass around the nipples. This physiologic condition can usually be seen in neonates (babies from one to four weeks of birth), adolescents, and the elderly. It can either occur bilaterally or unilaterally, where in only one breast is enlarged.

Pseudogynecomastia, or false gynecomastia should be differentiated from physiologic gynecomastia. Physiologic gynecomastia doesn’t involve glandular tissue hyperplasia whereas pseudogynecomastia is due to excessive fat deposits in one’s breast. Pseudogynecomastia is not pathologic or physiologic. Over time, fat deposits will not change in size or shape and a mammography will show no signs of malignancies.

Causes of Gynecomastia

 
Gynecomastia in essence is idiopathic and of an unknown cause, so treatment options for gynecomastia can vary. It develops as a result of an altered estrogen-androgen level in one’s body. Normally, sensitivity to estrogen increases thus inhibiting androgen sensitivity. Increased oxygen results to elongation and proliferation of mammary ducts, increased blood or fluid circulation, epithelial cell growth and proliferation of fibroblasts or connective tissues.

Testosterone is produced a hundred times more than estrogen, but its amount in circulation that can be seen in blood is about 300:1. In males, estrogen is produced by the conversion of androgens testosterone and androstenedione to estradiol and estrone, the active form of estrogen. The enzyme aromatase found in muscle, skin and adipose tissue is responsible for this interconversion.

Other Known Causes

Gynecomastia can result from medications, diseases, illegal drugs, alcohol, and aging.

It is caused by the following medications: cimetidine (an H2 antagonist), omeprazole (a benzoimidazole), spironolactone (an aldosterone antagonist), imatinib mesylate, finasteride (a nitrogenous steroid derivative used to treat symptoms of benign prostatic hyperplasia and to increase hair growth in male-pattern baldness) and anti-psychotic drugs. Finasteride acts by inhibiting the enzymatic conversion of testosterone to dihydrotestosterone, which lowers the circulating serum/blood level of testosterone. Anti-androgens such and gonadotropin-releasing hormone (GnRH), which is used for treating prostate cancers also has the same effect.

Other medications act mainly on the breast tissue which causes enlargement, or to increased circulation of prolactin (a hormone which causes breast development) production from the pituitary gland. It may also be caused by inhibiting dopamine, which is a natural prolactin-inhibiting factor in males. Performance enhancing food supplements, such as androstenedione, can also lead to breast enlargement by increasing estrogen action.  All of these things can make men self conscious and want to get rid of man boobs.

Gynecomastia may also be caused by defects in androgen receptors (inability of the cell to recognize androgens) as seen in Kennedy disease, chronic kidney disease, chronic liver disease, HIV, and other chronic diseases. Tumors of the adrenal glands, testes, pituitary glands, as well as hyperthyroidism and hypogonadism also have the same effect.

The part of the pituitary gland affected will mostly involve the anterior portion because this is the part that controls prolactin, growth hormone, and TSH (thyroid stimulating hormone). Diseases of the hypothalamus can also lead to low testosterone levels. Adrenal tumors cause increased androstenedione levels. In obesity, there is there increase of estrogen levels.

In liver cirrhosis, there is decreased estrogen clearance or breakdown, thus estrogen tends to stay in the body, which may lead to gynecomastia. Decreased testosterone production may also occur in genetic disorders such as Kleinfelter syndrome. Abuse of illegal drugs such as amphetamines, heroin, marijuana and anabolic steroids also cause gynecomastia. 
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