What are the causes of gynecomastia (enlargement of breast tissue in males)?

From the Guidelines

Gynecomastia is primarily caused by an imbalance between estrogen and testosterone levels in males, resulting in enlarged breast tissue, with the most common causes including physiological conditions such as puberty and aging, as well as pathological conditions like obesity, certain medications, and hormonal imbalances 1. The condition can manifest at any age and is often associated with various underlying factors. Key causes include:

• Physiological conditions: Puberty, affecting up to 70% of adolescent boys, and aging, affecting 24-65% of older men 1.
• Obesity: Fat tissue can convert testosterone to estrogen, leading to an imbalance 1.
• Medications: Certain drugs like spironolactone, ketoconazole, cimetidine, finasteride, antipsychotics, and some HIV medications can induce gynecomastia 1.
• Hormonal imbalances: Conditions such as hypogonadism, hyperthyroidism, and tumors secreting hormones can lead to gynecomastia 1.
• Other factors: Liver or kidney disease, excessive alcohol consumption, and anabolic steroid use can also contribute to the development of gynecomastia 1. It is essential to identify the underlying cause of gynecomastia to determine the appropriate treatment approach, which may involve addressing the underlying condition, discontinuing problematic medications, or in persistent cases, considering medication therapy or surgery 1.

From the Research

Causes of Gynecomastia

• Gynecomastia is a benign proliferation of glandular breast tissue in men, resulting from an imbalance between estrogen and androgen action at the breast tissue level 2, 3.
• The condition can be caused by various factors, including:
  • Physiologic changes during neonatal period, puberty, and senescence 4, 3.
  • Chronic conditions such as cirrhosis, hypogonadism, and renal insufficiency 4.
  • Use of medications, supplements, or illicit drugs, with an estimated 10-25% of cases attributed to drug-induced gynecomastia 5.
  • Tumors, although rare 4.

Drug-Induced Gynecomastia

• Certain medications have been implicated in the development of gynecomastia, including:
  • Spironolactone, cimetidine, ketoconazole, hGH, estrogens, hCG, anti-androgens, GnRH analogs, and 5-α reductase inhibitors, which have a definite association with gynecomastia 5.
  • Risperidone, verapamil, nifedipine, omeprazole, alkylating agents, HIV medications (efavirenz), anabolic steroids, alcohol, and opioids, which have a probable association with gynecomastia 5.

Evaluation and Management

• The evaluation of gynecomastia involves differentiating it from pseudogynecomastia and ruling out male breast carcinoma 2, 3.
• A selective laboratory and radiological work-up should be performed to identify the underlying cause 3.
• Treatment options include:
  • Reassurance and observation for pubertal gynecomastia, which often resolves spontaneously 3.
  • Medical therapy for persistent painful gynecomastia in adults 2, 3.
  • Surgical removal for chronic, bothersome gynecomastia 2, 3.