Endocrinology · Reproductive Endocrinology
The facts most likely to be tested
Gynecomastia is defined as the proliferation of glandular breast tissue in males, typically presenting as a firm, tender, subareolar mass.
Physiologic gynecomastia is common during puberty due to a transient estrogen-to-androgen imbalance and typically resolves spontaneously within two years.
Pathologic gynecomastia requires evaluation for medication side effects, cirrhosis, chronic kidney disease, or testicular tumors.
Common offending medications include spironolactone, ketoconazole, cimetidine, finasteride, and antipsychotics.
Initial diagnostic workup for persistent or symptomatic gynecomastia includes serum TSH, LH, FSH, testosterone, estradiol, and beta-hCG.
Elevated beta-hCG levels in the setting of gynecomastia are highly suggestive of a testicular germ cell tumor.
Treatment for symptomatic, non-resolving gynecomastia includes tamoxifen (a selective estrogen receptor modulator) or surgical excision if the condition is long-standing and fibrotic.
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A 22-year-old male presents to the clinic complaining of bilateral breast tenderness and enlargement that has persisted for 18 months. He denies any use of illicit drugs, supplements, or prescription medications. Physical examination reveals a firm, 3-cm subareolar mass bilaterally without nipple discharge or skin retraction. Testicular examination is notable for a painless, firm nodule on the right testicle. Laboratory studies reveal elevated serum beta-hCG and normal testosterone levels.
What is the most likely diagnosis for the testicular finding?
Testicular germ cell tumor (specifically a choriocarcinoma or mixed germ cell tumor)
The patient's gynecomastia is secondary to a testicular tumor producing beta-hCG, which stimulates the Leydig cells to increase estrogen production, testing the association between elevated beta-hCG and testicular malignancy.
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Etiology / Epidemiology
Common in puberty, aging, and hypogonadism. Driven by estrogen-androgen imbalance.
Clinical Manifestations
Palpable subareolar firm, rubbery tissue. Usually bilateral and tender.
Diagnosis
Clinical diagnosis. Mammography or ultrasound if malignancy suspected.
Treatment
Stop offending agent. Tamoxifen for persistent, painful cases.
Prognosis
Physiologic cases resolve in 6-24 months. Monitor for malignancy.
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Epidemiology & Etiology
Occurs in up to 60% of adolescent males and 40% of older men. Primary causes include testicular failure, cirrhosis, and hyperthyroidism. Always screen for medication-induced causes first.
Pertinent Anatomy
True gynecomastia involves proliferation of ductal and stromal breast tissue. It is distinct from pseudogynecomastia, which is purely adipose tissue deposition. The tissue is typically located directly beneath the areola.
Pathophysiology
Results from an increased estrogen-to-androgen ratio. This occurs via increased estrogen production, decreased androgen production, or androgen receptor blockade. Chronic liver disease impairs estrogen metabolism, while alcohol use further disrupts the hypothalamic-pituitary-gonadal axis.
Clinical Manifestations
Presents as a firm, mobile, tender mass located centrally. Unilateral or fixed masses, nipple discharge, or skin dimpling are red flags for male breast cancer. Always assess for signs of hypogonadism such as decreased libido or erectile dysfunction.
Diagnosis
Diagnosis is primarily clinical. Mammography is the gold standard to differentiate true gynecomastia from carcinoma. If suspected hypogonadism, order serum testosterone, LH, and estradiol levels.
Treatment
Management focuses on identifying and removing the offending agent. For painful or persistent cases, tamoxifen (a selective estrogen receptor modulator) is the treatment of choice. Surgery is reserved for long-standing, fibrotic tissue that fails medical therapy.
Prognosis
Physiologic gynecomastia is self-limiting and typically resolves within 2 years. Persistent cases require evaluation for underlying endocrine disorders or malignancy.
Differential Diagnosis
Pseudogynecomastia: soft, non-tender adipose tissue
Male Breast Cancer: hard, fixed, eccentric mass
Lipoma: soft, mobile, non-tender fatty tumor
Abscess: erythematous, warm, fluctuant mass
Neurofibroma: firm, skin-colored, associated with café-au-lait spots