Ultrasound assessment of breast development: distinction between premature thelarche and precocious puberty

OBJECTIVE. We analyzed the correlation between breast development and ultrasound-measured breast bud diameter. We also evaluated different breast ultrasound findings in pediatric subjects with precocious puberty and premature thelarche while comparing bone age and hormone levels. MATERIALS AND METHODS. We performed a retrospective study with a sample of 90 girls (mean age, 7.8 years) who underwent breast ultrasound for evaluation of early breast development between March 2011 and February 2013. We evaluated breast ultrasound grade, bud diameter, and clinical characteristics including bone age and hormone levels. Among the 90 girls, 69 were up to 8 years old (mean age, 7.3 years). We divided them into healthy, precocious puberty, and premature thelarche groups and evaluated the clinicoradiologic findings for each group. RESULTS. Breast ultrasound grade was correlated with age, bone age, bud diameter, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol (E2). Bud diameter was correlated with age, bone age, LH, FSH, and E2. However, the difference between bone age and chronological age was not correlated with ultrasound grade or bud diameter. Among 69 girls up to 8 years old, including 11 healthy girls (15.9%), 26 girls with precocious puberty (37.7%) (mean [SD] age, 7.3 years), and 32 girls with premature thelarche (46.4%) (mean age, 7.2 years), there were no significant differences in other variables except values for bone age (p = 0.001) and difference between bone age and chronological age (p < 0.001). CONCLUSION. Breast ultrasound might be useful for evaluating sexual development with respect to bud diameter or ultrasound grade. However, its ability to distinguish precocious puberty from premature thelarche is limited.