Manuel A. Torres-Salichs MD,FACS Surgical Oncology, Breast Surgeon

Edileidis Tarrio, ARNP-BC, OCN






Gynecomastia is a benign enlargement of the male breast resulting from proliferation of the glandular component of the breast. It is the most common reason for male breast evaluation. It can occur in men of all ages. Gynecomastia is the result of an imbalance of estrogens and androgens. The imbalance is between the stimulatory effect of estrogen and the inhibitory effect of androgen. There is a decrease ratio of testosterone to estrogen. This imbalance can result in the enlargement of the male breast. It can occur in boys and men of all age. It is most common in infancy, adolescence, and middle age to older men.

Gynecomastia occurs in 60% to 90% of male infants. It resolves in most cases and it is the result of breast stimulation by the mother’s estrogen. In most cases the condition resolves in 1 to 3 years. Persistent gynecomastia is seen in less than 5% of affected boys
Gynecomastia is usually a transient condition of breast development occurring in 10 to 16 year old boys. Up to 65% of adolescents are affected and the peak incidence is at 14 years of age. This condition is believed to be caused by an increased conversion of adrenal androgens to estrogens
Older Men:
It is seen in approximately 50% of older men. It is the result of a decreased production of testosterone in the testicles and increased conversion of androgens to estrogens (by the aromatase enzyme) as body fat increases. It may also be caused by several types of medications

Gynecomastia is caused by an altered ratio of estrogen (female hormone) in relation to androgens (male hormones). It can also be due to an increased sensitivity to normal levels of estrogens. These changes can cause elongation and branching of the breast ducts, fibrosis, and increased vascularity.

Males produce estrogens by converting the testosterone and androstenedione (male hormones) to estrone and estradiol (female hormones) by an enzyme named aromatase. This process occurs mainly in the fat, muscle and skin. In an adult the normal production ratio of androgen to estrogen is 100:1. The ratio of testosterone to estrogen in the blood circulation is 300:1.


Conditions Associated with Gynecomastia:

Idiopathic: (no detectable abnormality) (25%)

Pubertal: (25%)


  • Testicular (3%)
  • Pituitary
  • Adrenal
  • Liver
  • Lymphoma

Endocrine Disorders:

  • Hypogonadism (8%)
  • Androgen insensitivity
  • High aromatase enzymes
  • Testicular injury/ regression
  • Adrenal hyperplasia
  • Hyperthyroidsm (1.5%)
  • Viral orchitis

Chronic Illnesses:

  • Malnutrition
  • Liver disease (cirrhosis 8%)
  • Renal disease (1%)
  • AIDS
  • Ulcerative Colitis


Medications: (10- 20%)


  • Estrogens
  • Androgens and anabolic steroids
  • Human chorionic gonadotropin

Androgen Antagonists:

  • Ketoconazole
  • Flutamide
  • Metronidazole
  • Finasteride
  • Spironolactone

Antiulcer Drugs:

  • Cimetidine
  • Omeprazole
  • Ranitidine



Psychoactive Drugs:

  • Tricyclic antidepressants
  • Phenothiazines
  • Diazepam

Cardiovascular Agents:

  • Calcium channel blockers
  • Angiotensin-converting enzyme inhibitors
  • Digitoxin
  • Methyldopa


Antituberculosis Agents:

Antiviral Medications:

  • Protease inhibitors


  • Marijuana
  • Heroine
  • Methadone
  • Alcohol (increases testosterone clearance from the circulation)
  • Amphetamines
  • Phenytoin


Laboratory Profile:

Male adolescents with breast tissue more than 4 centimeters in diameter should undergo laboratory testing. If any of these tests are abnormal, further evaluation should be followe by an endocrinologist.

  • B- Human chorionic gonadotropin
  • Dehidroepiandrostenedione sulfate
  • Luteinizing hormone/follicle-stimulating hormone
  • Testosterone
  • Estradiol
  • Prolactine
  • Free thyroxine
  • Thyrotropin
  • Chemistry panel


Imagine Studies:
Imaging studies are indicated in some cases if there is a suspicion of a breast cancer or tumor. These include a bilateral mammogram and breast ultrasound. A testicular ultrasound is indicated for evaluation of a testicular mass or for elevated levels of estradiol.

Medical Treatment:
Generally, no treatment is required for physiologic gynecomastia:

It is unlikely that any medical therapy will result in regression if gynecomastia has been present for 12 months or longer. Pubertal gynecomastia resolves in approximately 90% of patients. Identifying and managing the primary disorder often alleviates breast enlargement. Medications used to treat gynecomastia include clomiphene, tamoxifen, danazol and aromatase inhibitors.

Subcutaneous mastectomy should be considered for patients with long-standing gynecomastia or in symptomatic patients that have failed medical treatment. Liposuction may be warranted in some cases such as pseudogynecomastia. Extensive plastic surgery and reconstruction is required in patients with significant gynecomastia.