pseudopuberty, or exposure to exogenous estrogens, and careful follow-up with the primary physician is required Juvenile Breast Hypertrophy Juvenile breast hypertrophy is a rare disorder characterized by sudden, rapid, massive breast enlargement at a time of intense endocrine stimulation, usually between and 16 years of age, after onset of menarche It is believed to result from end-organ hypersensitivity to estrogen The hypertrophy is usually bilateral and asymmetric and may progress at an alarming rate over 36 months The differential diagnosis of this lesion includes cystosarcoma phyllodes, juvenile fibroadenoma, and precocious puberty; however, true endocrine or neoplastic lesions are uncommon In some cases, the hypertrophy regresses in to years, but referral to a breast surgeon is always indicated; breast reduction or even total ablation may become necessary This disorder is often associated with extreme emotional and psychosocial distress for patients and families Gynecomastia Gynecomastia is a term commonly used to describe a broad spectrum of clinical breast lesions in boys, including excess breast tissue, breast enlargement, and masses of tissue below the nipple that are discrete and nonadherent to the chest wall, and may occur unilaterally or bilaterally Gynecomastia has been described as the male equivalent of fibrocystic changes in the female breast, based on histologic evidence Typically, local breast tissue demonstrates evidence of mild estrogen–testosterone hormone imbalance, resulting from physiologic changes (neonatal, puberty, aging); exogenous medications; tumors of the testes, adrenal glands, and lungs; metabolic conditions (cirrhosis, hyperthyroidism, renal disease); or hypogonadism From a clinical perspective, gynecomastia occurs in about 50% of all boys between the ages of 11 and 18 years and typically lasts about years It can be associated with growth spurts and can also cause a significant degree of pain The glandular enlargement is about cm and resembles the early stages of female breast budding More commonly, gynecomastia presents to the emergency physician because of associated anxiety in adolescent boys If the patient has normal-sized genitalia and none of the predisposing conditions listed earlier, reassurance is all that is required, though inquiry about both prescription and illicit use of drugs should be sought There is often particular concern about gynecomastia in obese boys, since they may appear to have an overabundance of fatty tissue in the breast region Of note, the incidence of true gynecomastia is not