Pathology: A large glandular mass of male breast tissue, surgically removed Microscopic image showing gynecomastoid hyperplasia, the cellular changes seen in<unk>  H&E stain The causes of common<unk>  remain uncertain, but are thought to result from an imbalance between the actions of estrogen and androgens at the breast tissue. Breast prominence can result from enlargement of glandular breast tissue, chest adipose tissue (fat) and skin, and is typically a combination. As in females, estrogen stimulates the growth of breast tissue in males. In addition to directly stimulating male breast tissue growth, estrogens indirectly decrease secretion of testosterone by suppressing luteinizing hormone secretion, resulting in decreased testicular secretion of testosterone. Furthermore, estrogens can increase blood levels of the protein sex hormone-binding globulin (SHBG), which binds free testosterone (the active form) leading to decreased action of testosterone in male breast tissue. Primary hypogonadism (indicating an intrinsic problem with the testes in males) leads to decreased testosterone synthesis and increased conversion of testosterone to estradiol potentially leading to a<unk>  appearance. Klinefelter syndrome is a notable example of a disorder that causes hypogonadism and<unk> , and has a higher risk of breast cancer in males (20–50 times higher than males without the disorder). Central hypogonadism (indicating a problem with the brain) leads to decreased production and release of luteinizing hormone (LH, a stimulatory signal for endogenous steroid hormone synthesis) which leads to decreased production of testosterone and estradiol in the testes. Individuals who have cirrhosis or chronic liver disease may develop<unk>  for several reasons. Cirrhotics tend to have increased secretion of the androgenic hormone androstenedione from the adrenal glands, increased conversion of this hormone into various types of estrogen, and increased levels of SHBG, which leads to decreased blood levels of free testosterone. Around 10–40% of individuals with Graves' disease (a common form of hyperthyroidism) experience<unk> . Increased conversion of testosterone to estrogen by increased aromatase activity, increased levels of SHBG and increased production of testosterone and estradiol by the testes due to elevated levels of LH cause the<unk> . Proper treatment of the hyperthyroidism can lead to the resolution of the<unk> . Medications are known to cause<unk>  through several different mechanisms. These mechanisms include increasing estrogen levels, mimicking estrogen, decreasing levels of testosterone or other androgens, blocking androgen receptors, increasing prolactin levels, or through unidentified means. High levels of prolactin in the blood (which may occur as a result of certain tumors or as a side effect of certain medications) has been associated with<unk> . A high level of prolactin in the blood can inhibit the release of gonadotropin-releasing hormone and therefore cause central hypogonadism. Receptors for prolactin and other hormones including insulin-like growth factor 1, insulin-like growth factor 2, luteinizing hormone, progesterone, and human chorionic gonadotropin have been found in male breast tissue, but the impact of these various hormones on<unk>  development is not well understood.
Gynecomastia
Breast atrophy
Pattern hair loss
Post-vacation blues
Adipomastia
Trichomegaly
Breast hypertrophy
Clitoromegaly