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Interpretation of laboratory tests in the evaluation of unilateral or bilateral gynecomastia in phenotypically male children and adolescents*
Initial tests Additional evaluation/supportive findings Potential cause(s)
hCG Estradiol Testosterone LH DHEA
Increased Normal Normal Normal Normal Testicular US: Normal Extragonadal germ-cell tumor or hCG-secreting nontrophoblastic neoplasm*
Testicular US: Mass Testicular germ cell tumor
Normal Increased Normal Increased Normal Karyotype Possible ovotesticular DSD
Normal Increased Normal Normal or decreased Increased Adrenal imaging: Adrenal mass Adrenal neoplasm
Adrenal imaging: Normal Possible CAH
Normal Increased Normal Normal or decreased Normal

Testicular US: Normal

Adrenal imaging: Normal		 Increased extraglandular aromatase activity (eg, aromatase excess syndrome)
Testicular US: Mass Sertoli-cell tumor
Normal Increased Increased Normal or decreased Normal Testicular US: Mass Leydig-cell tumor or Leydig-cell and Sertoli-cell tumor
Normal Normal Increased Increased Normal

TSH: Decreased

Thyroxine: Increased		 Hyperthyroidism

TSH: Normal

Thyroxine: Normal		 Androgen resistance (eg, partial androgen insensitivity)
Normal Normal DecreasedΔ Increased Normal Refer to UpToDate content on primary hypogonadism in males Primary hypogonadism
Normal Normal DecreasedΔ Normal or decreasedΔ Normal Serum prolactin: Normal Secondary hypogonadism
Serum prolactin: Elevated Prolactin-secreting pituitary tumor◊
Normal Normal Normal Normal Normal NA Pubertal or idiopathic gynecomastia
Our suggested initial laboratory evaluation for phenotypically male children and adolescents with unilateral or bilateral gynecomastia in whom a potential cause is not identified on history and physical examination includes measurement of early morning hCG, estradiol, LH, testosterone, and DHEA. The reference range for hormones may vary by age, sexual maturity rating, and clinical laboratory. All patients may not fit into the categories in the table above.
hCG: human chorionic gonadotropin; LH: luteinizing hormone; DHEA: dehydroepiandrosterone; US: ultrasonography; CT: computed tomography; MRI: magnetic resonance imaging; TSH: thyroid-stimulating hormone; NA: not applicable; DSD: disorder of sex development; CAH: congenital adrenal hyperplasia.
* Further evaluation may include chest radiography and abdominal computed tomography.
¶ Referral to a pediatric endocrinologist is recommended. Refer to UpToDate content on atypical genitalia and congenital adrenal hyperplasia for more information.
Δ Decreased testosterone and decreased LH are normal findings in prepubertal-age boys and not helpful in the evaluation of gynecomastia.
◊ Further evaluation may include magnetic resonance imaging of the head.
References:
  1. Braunstein GD. Clinical practice. Gynecomastia. N Engl J Med 2007; 357:1229.
  2. Ma NS, Geffner ME. Gynecomastia in prepubertal and pubertal men. Curr Opin Pediatr 2008; 20:465.
  3. Misra M, Sagar P, Friedmann AM, et al. Case records of the Massachusetts General Hospital. Case 12-2016. An 8-Year-Old Boy with an Enlarging Mass in the Right Breast. N Engl J Med 2016; 374:1565.
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