Breast hypertrophy is a rare condition that is characterized by abnormal breast enlargement due to excessive tissue growth. Although usually idiopathic, hormonal etiologies include aromatase excess syndrome, hyperprolactinemia, and increased sensitivity to estrogen and progesterone. Clinical features include disproportionately large breasts, mastalgia, inframammary intertrigo, trapezius hypertrophy, and neck, shoulder, and upper back pain. Breast hypertrophy is a clinical diagnosis; laboratory studies and imaging may be indicated to evaluate for an underlying etiology or to rule out other diagnoses. Surgical breast reduction (reduction mammoplasty) is the mainstay of treatment for symptomatic breast hypertrophy. Conservative measures (e.g., proper breast support, upper body physiotherapy) and pharmacotherapy are alternatives when surgery is not feasible.
- Breast hypertrophy (also termed macromastia): excessive proliferation of breast connective tissue, glandular hypertrophy, and/or fatty tissue, resulting in abnormal breast enlargement 
- Juvenile breast hypertrophy: the rapid enlargement of one or both breasts that usually begins around menarche 
- Gigantomastia: extreme breast hypertrophy 
- Typically idiopathic; other causes include:
- Risk factors
- Obtain a thorough history. 
- Perform a clinical breast examination (CBE). 
- Assess for masses and asymmetry.
- Evaluate the inframammary folds for intertrigo or other abnormalities.
Laboratory studies 
- Not routinely indicated
- Estradiol, progesterone, prolactin, FSH, LH, and/or urine HCG may be considered to identify potential causes (e.g., hormonal imbalance, pregnancy) or rule out alternative diagnoses.
- Indications: symptomatic breast hypertrophy
Conservative management 
- Indications 
Consider alternatives to progestin-containing contraception in adolescents. Exogenous progestin-only contraception may initially exacerbate breast hypertrophy, but it is not associated with continued breast tissue growth.