SKINIPEDIA - Skin Obesity Problems: Gynecomastia
Obesity and Skin Problems: Gynecomastia ("male breasts")
work by Mark R Allee, MD, Associate Professor, Department of Medicine, University of Oklahoma Health Sciences Center Coauthor(s): Mary Zoe Baker, MD, Professor, Department of Medicine, Section of Endocrinology, Metabolism and Hypertension, University of Oklahoma; Medical Director, University of Oklahoma Physicians, Medicine Specialty Clinic, General Medicine Clinic and Medicine Residents' Clinic.
Gynecomastia is a benign enlargement of the male breast resulting from a
proliferation of the glandular component of the breast. Gynecomastia is
defined clinically by the presence of a rubbery or firm mass extending
concentrically from the nipples. The condition known as
pseudogynecomastia, or lipomastia, is characterized by fat deposition
without glandular proliferation. Although gynecomastia is usually
bilateral, it can be unilateral.
Recent Studies
In a Flemish study of 1679 adolescents, aged 14-15 years, Den Hond et al investigated the effects of pollutants on sexual maturation. Their data indicated that higher blood levels of lead increased the risk of gynecomastia in the study's subjects, while higher serum levels of hexachlorobenzene decreased the risk.
Ramadan et al assessed breast vascularity in 54 male patients, aged 11-27 years, with gynecomastia. Using ultrasonographic scanning, the authors found a strong correlation between the progression of breast development and that of arterial and venous blood flow. They concluded that vascular structures ought to be considered a component of gynecomastia......
Gynecomastia results from an altered estrogen-androgen balance, in favor of estrogen, or from increased breast sensitivity to a normal circulating estrogen level. The imbalance is between the stimulatory effect of estrogen and the inhibitory effect of androgen. Estrogens induce ductal epithelial hyperplasia, ductal elongation and branching, proliferation of the periductal fibroblasts, and an increase in vascularity. The histologic picture is similar in male and female breast tissue after exposure to estrogen.
Estrogen production in males results mainly from the peripheral conversion of androgens (testosterone and androstenedione) — through the action of the enzyme aromatase, mainly in muscle, skin, and adipose tissue — to estradiol and estrone.
The normal production ratio of testosterone to estrogen is approximately 100:1. The normal ratio of testosterone to estrogen in the circulation is approximately 300:1.
Frequency - United States
Gynecomastia is the most common reason for male breast evaluation. The condition is common in infancy and adolescence, as well as in middle-aged to older adult males. One estimate is that 60-90% of infants have transient gynecomastia due to the high estrogen state of pregnancy.
The next peak of occurrence is during puberty, with a prevalence ranging from 4-69%. Some reports have shown a transient increase in estradiol concentration at the onset of puberty in boys who develop gynecomastia. Pubertal gynecomastia usually has an onset in boys aged 10-12 years. It generally regresses within 18 months, and persistence is uncommon in men older than 17 years.
The third peak occurs in older men, with a prevalence of 24-65%. Gynecomastia in adults is often multifactorial. Increased aromatization of testosterone to estradiol and the gradual decrease of testosterone production in the aging testes most often account for gynecomastia in adult males. Older men are also more likely to take medications associated with gynecomastia than are younger men.
Estimates suggest the following etiologies in males seeking medical attention for gynecomastia:
- Persistent pubertal gynecomastia – 25%
- Drugs – 10-25%
- No detectable abnormality – 25%
- Cirrhosis or malnutrition – 8%
- Primary hypogonadism – 8%
- Testicular tumors – 3%
- Secondary hypogonadism – 2%
- Hyperthyroidism - 1.5%
- Chronic renal insufficiency – 1%