| | Associated clinical features |
| Physiologic causes |
| Neonatal | - May be associated with galactorrhea; usually resolves spontaneously within the first year of life
|
| Pubertal | - Occurs at mid-puberty: during peak height velocity at age 12 to 14 years; pubic hair SMR stage 3 to 4; testicular volume 8 to 10 mL
|
| Pathologic causes |
| Drugs |
| Exogenous estrogen | - Source of exogenous estrogen (eg, combined oral contraceptive pills, topical estrogen cream)
|
| Other drugs | - History of exposure to drug or other substances associated with gynecomastia (refer to UpToDate content on drugs that cause gynecomastia)
|
| Hypogonadism |
| Primary (hypergonadotropic) |
| | - Tall, thin body habitus; small firm testes in pubertal-aged males
|
| | - One or both testes not within the scrotum (or history of testis that is not within the scrotum)
|
- Defect in testosterone synthesis (eg, 17-ketosteroid reductase deficiency)
| - Atypical genitalia; undervirilization
|
- Acquired primary hypogonadism
| - History of testicular insult or injury (eg, surgery, radiation, systemic illness, etc)
|
| Secondary (hypogonadotropic) |
- Acquired secondary hypogonadism
| - Insult to hypothalamic-pituitary axis (eg, surgery, radiation, trauma, etc)
|
| | |
| Tumors |
| Testicular cancer (Leydig or Sertoli cell) | - Testicular mass; increased risk with history of cryptorchidism (any testicular cancer); increased risk in Peutz-Jeghers syndrome (Sertoli cell tumors)
|
| Feminizing adrenal tumor | |
| Lactotroph adenoma (prolactinoma) | - Galactorrhea, hypogonadism, vision problems, headaches
|
| hCG-producing tumors |
| | - Testicular mass; increased risk with history of cryptorchidism
|
- Extragonadal germ cell tumor (eg, mediastinal, retroperitoneal, intracranial)
| - May be detected with chest or abdominal imaging
|
- Nontrophoblastic hCG-producing tumor
| - May be detected with imaging (chest, abdomen, brain)
|
| Other causes |
| Chronic liver or kidney disease/malnutrition | - Underweight; findings associated with chronic liver or kidney disease (eg, hepatomegaly, edema, etc)
|
| Hyperthyroidism | - Goiter, accelerated growth, weight loss, ophthalmopathy, tachycardia, increased appetite, tremor
|
| Aromatase excess syndrome | - Accelerated early linear growth, prepubertal gynecomastia, testicular failure
|
| Androgen resistance (eg, partial androgen insensitivity) | - Atypical genitalia; undervirilization; muscle fasciculations, weakness, and calf hypertrophy (X-linked spinal and bulbar muscular atrophy)
|
| Congenital adrenal hyperplasia |
- 11-beta-hydroxylase deficiency
| - Premature adrenarche, early puberty, accelerated linear growth, hypertension
|
- 3-beta-hydroxysteroid dehydrogenase deficiency
| - Atypical genitalia, undervirilization
|
- Late-onset 21-hydroxylase deficiency
| - Premature adrenarche with advanced bone age, accelerated linear growth during childhood, acne
|
| Ovotesticular difference of sex development (previously "true hermaphroditism") | - Atypical genitalia (presence of both ovarian follicular and testicular tubular tissue in a single individual); undervirilization
|
