Evaluation of pelvic ultrasonography in the diagnosis and differentiation of various forms of sexual precocity in girls.

OBJECTIVES: This study was conducted to assess the role of pelvic ultrasound variables in discriminating between normal girls and girls with different forms of sexual precocity, and to establish reliable cut-off limits of pelvic ultrasound measurements for differentiating between these conditions. METHODS: Eighty-eight girls with different forms of sexual precocity (23 with premature thelarche, 15 with premature pubarche and 50 with central precocious puberty) were enrolled. All diagnoses were based on clinical examination with confirmation using the gonadotropin-releasing hormone-stimulation test. Additionally, 81 prepubertal girls, aged 0-10 years, were included as a control group. For statistical analysis and to facilitate comparisons, the groups were subdivided by age intervals (0-6, > 6-8 and > 8-10 years). All subjects underwent pelvic ultrasound examination for the measurement of uterine length, uterine volume, ovarian volume and the anteroposterior diameter at the fundus divided by the anteroposterior diameter at the cervix (fundal/cervical ratio, (F/C)). Finally, the morphological appearance of the ovaries was assessed. RESULTS: Patients with central precocious puberty had significantly higher values for all the ultrasound variables (with the exception of uterine length in the 1-6-year age group) in comparison to normal girls. Patients with premature thelarche and patients with premature pubarche showed similar pelvic ultrasound parameters to those of normal girls. Ovarian volume was the best parameter for identifying patients with central precocious puberty (a cut-off of 3.04 cm(3) had a sensitivity of 100% and a specificity of 97.1% for age interval 0-6 years, a cut-off of 3.35 cm(3) had a sensitivity of 100% and a specificity of 89.5% for age interval > 6-8 years, and a cut-off of 4.46 cm(3) had a sensitivity of 80.8% and a specificity of 88.5% for age interval > 8-10 years). Uterine length was the best parameter for distinguishing between patients with central precocious puberty and patients with premature thelarche (a cut-off of 3.185 cm had a sensitivity of 85.7% and a specificity of 91.7% for age interval 0-6 years, and a cut-off of 3.83 cm had a sensitivity of 82.4% and a specificity of 90.9% for age interval > 6-8 years). CONCLUSIONS: Ultrasound examination of the uterus and ovaries could serve as a complementary tool for the diagnosis of central precocious puberty and, consequently, for the early initiation of appropriate treatment.