Published on 25/03/2015 by admin
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Last modified 25/03/2015
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Chapter 579 Gynecomastia
Omar Ali, Patricia A. Donohoue
Gynecomastia, the proliferation of mammary glandular tissue in the male, is a common condition. True gynecomastia (the presence of glandular breast tissue) needs to be distinguished from pseudogynecomastia due to accumulation of adipose tissue in the area of the breast that is commonly seen in overweight boys. True gynecomastia is characterized by the presence of a palpable fibroglandular mass at least 0.5 cm in diameter, located concentrically beneath the nipple and areaolar region.
Physiologic Forms of Gynecomastia: Gynecomastia occurs in many newborn males as a result of normal stimulation by maternal estrogen; the effect usually disappears in a few weeks. It is then extremely rare in prepubertal boys, in whom it should always be investigated to identify the cause. It is very common in puberty.
Neonatal Gynecomastia: Transient gynecomastia occurs in 60-90% of male newborns secondary to exposure to estrogens during pregnancy. Breast development may be asymmetrical and galactorrhea is seen in approximately 5%. Most cases resolve within 4-8 wk of birth, but a few can last as long as 12 mo.
Pubertal Gynecomastia: During early to mid-puberty, up to 65% of boys develop various degrees of subareolar hyperplasia of the breasts. Incidence peaks at 14 yr of age, at Tanner stage 3-4 and at a testicular volume of 5-10 mL. Physiologic pubertal gynecomastia may involve only 1 breast; it is not unusual for both breasts to enlarge at disproportionate rates or at different times. Tenderness of the breast is common but transitory. Spontaneous regression may occur within a few months; it rarely persists longer than 2 yr. Significant psychosocial distress may be present, especially in obese boys with relatively large breasts.
The cause is thought to be an imbalance between estrogen and androgen action at the level of breast tissue. Testing usually fails to reveal any significant difference in circulating estrogen and androgen levels between affected and unaffected males, but minor degrees of imbalance in free hormone levels may still be present. Other hormones including leptin and luteinizing hormone (LH) may directly stimulate breast development and may play an important role in pubertal gynecomastia. Some cases may be due to an increased sensitivity to estrogens and/or relative androgen resistance in the affected tissue. As androgen levels continue to rise in later puberty, most cases resolve.
Pathological Gynecomastia:
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