Progression of premature thelarche to central precocious puberty.

To evaluate whether girls with premature thelarche progress to central precocious puberty (CPP) and to analyze their clinical and hormonal characteristics, we retrospectively examined 100 girls with premature thelarche who were followed for several years. Fourteen of the patients with characteristics diagnostic of premature thelarche (isolated breast development before age 8 years, bone age advancement within 2 SD of normal, normal growth velocity, follicle-stimulating hormone-predominant response to luteinizing hormone-releasing hormone) progressed during follow-up to precocious or early central puberty (progressive breast size increase, bone age acceleration, and significant decrease in predicted adult height). The chronologic age of this group of 14 girls was 5.1 +/- 2.0 years at the onset of premature thelarche and 7.8 +/- 0.6 years (mean +/- SD) after progression to central early or precocious puberty. Pelvic ultrasonography showed significant differences in measurements between the time of diagnosis of premature thelarche and progression to CPP. Nine of these patients required treatment, three with cyproterone acetate and six with luteinizing hormone-releasing hormone analogs, and all responded as expected for classic CPP. At baseline evaluation, no clinical or hormonal characteristics could be established that separated the 14 children who progressed to precocious or early puberty from the 86 girls who did not. We conclude that premature thelarche is not always a self-limited condition and may sometimes accelerate the timing of puberty.