Breast US in children and adolescents

Ultrasonography (US) is of value in the evaluation and characterization of breast masses in children. Most masses represent either normal breast tissu e, cysts, or fibroadenomas. Premature thelarche may be unilateral, and norm al breast tissue is found at US. Cysts are commonly retroareolar; when they become infected, they appear sonographically as a complex mass. Fibroadeno ma is the most frequent breast tumor in adolescent girls, and it is usually solitary, homogeneous, and hypoechoic. Malignant breast lesions are very r are in children; most are due to metastatic disease secondary to rhabdomyos arcoma, leukemia, lymphoma, and neuroblastoma, and their US appearance is n onspecific. Gynecomastia in boys can be mimicked by general obesity and pec toral hypertrophy; US is helpful in the diagnosis, especially when gynecoma stia is asymmetric. Most breast lesions in children and adolescents are ben ign, and surgery should be avoided to prevent later deformity. US is the id eal imaging modality to evaluate breast lesions and may be used to guide a fine-needle aspiration biopsy. Color Doppler US evaluation is helpful; cyst s are avascular, fibroadenomas may be avascular or hypovascular, and absces ses show peripheral increased flow. Bloody nipple discharge is more common in prepubertal patients, may occur in infants, and may be secondary to mamm ary ductal ectasia. Discharge commonly resolves spontaneously, and findings at US are frequently normal.