Gynaecomastia

Overview – Gynaecomastia

Gynaecomastia refers to the benign enlargement of male breast tissue due to an imbalance between oestrogens and androgens. This condition is relatively common, particularly during puberty and old age, and can also signal underlying endocrine, hepatic, or testicular pathology. While often self-limiting, persistent or pathological cases may require medical or surgical management.

Definition

Gynaecomastia is defined as the benign proliferation of glandular breast tissue in males, due to a relative excess of oestrogens (which stimulate breast tissue) and/or deficiency of androgens (which inhibit it).

Aetiology

• Physiological Causes:
  • Puberty
  • Old age
• Pathological Causes:
  • Liver disease (e.g. cirrhosis, chronic alcohol use)
  • Testicular atrophy or testicular cancer
  • Klinefelter’s syndrome (47,XXY)
  • Hyperthyroidism
  • Prostate cancer treatment (anti-androgens)
• Drug-Induced:
  • Anabolic steroids
  • Anti-testosterone therapy
  • Some anti-epileptics, spironolactone, and digoxin (not originally listed but may be added for completeness in clinical practice)

Morphology / Pathophysiology

Pathogenesis

• Oestrogen:Androgen imbalance → hypertrophy of rudimentary breast tissue in the male breast
• Can be unilateral or bilateral

Morphology

• Macroscopic:
  • Breast tissue enlargement resembling adolescent female breast
• Microscopic:
  • Ductal (epithelial) hyperplasia
  • Fibrous stromal proliferation
  • Absence of acini (a key feature distinguishing it from female breast tissue)

Clinical Features

• Gradual or sudden enlargement of breast tissue
• May be tender or painless
• Often bilateral, but can be unilateral
• Frequently asymptomatic, discovered incidentally

Investigations

• Clinical history and physical exam
• Hormonal assays (e.g. testosterone, oestrogen, LH/FSH, prolactin)
• Liver function tests
• Thyroid function tests
• Scrotal ultrasound (if suspecting testicular pathology)
• Karyotyping (if suspecting Klinefelter’s syndrome)

Management

• Medical:
  • Anti-oestrogens:
    • Tamoxifen
    • Raloxifene
    • Clomifene
• Surgical:
  • Breast reduction surgery in persistent or distressing cases
• Treat underlying cause if pathological (e.g. stop causative drug, treat liver disease)

Complications

• Psychological distress or embarrassment
• May mimic breast cancer (always consider malignancy in unilateral, hard, fixed masses with nipple changes)
• Underlying serious systemic disease (e.g. cancer, endocrine disorders)

Differential Diagnosis

• Male breast carcinoma
• Lipoma
• Pseudogynaecomastia (due to fat accumulation, not glandular tissue)
• Mastitis or abscess

Summary – Gynaecomastia

Gynaecomastia is a benign enlargement of male breast tissue due to an imbalance between oestrogens and androgens. It can occur physiologically in puberty and old age, or pathologically in the context of liver disease, testicular abnormalities, medications, or hormonal therapies. Management includes identifying the underlying cause, using anti-oestrogen therapy, or performing surgery. For a broader context, see our Reproductive Health Overview page.