PELVIC ULTRASONOGRAPHY - EARLY DIFFERENTIATION BETWEEN ISOLATED PREMATURE THELARCHE AND CENTRAL PRECOCIOUS PUBERTY

We examined 55 girls with isolated premature thelarche between the age s of 0.3 and 7.4 years (group A), 20 children with central precocious puberty between 2.1 and 7.7 years of age and 101 age-matched controls. The children with precocious puberty were divided according to distri bution of pubic hair into group B (Tanner stages PH1, B2-3; n = 11), r epresenting an early stage of the disorder, and group C (stages PH2-3, B3-4; n = 9), representing an advanced stage. Uterine and ovarian vol umes were measured sonographically peak serum levels of luteinizing, h ormone and follicle-stimulating hormone were determined after intraven ous administration of luteinizing hormone-releasing hormone. The mean uterine and ovarian volumes were significantly greater in children wit h precocious puberty than in controls (group B: uterine volume: 3.8 +/ - 2.0 ml vs 0.9 +/- 0.3 ml for controls, P < 0.001; ovarian volume: 2. 2 +/- 1.3 ml vs 0.6 +/- 0.2 ml for controls, P < 0.01; group C: uterin e volume: 8.0 +/- 4.4 ml vs 1.0 +/- 0.3 ml for controls, P < 0.01; ova rian volume; 2.6 +/- 1.3 ml vs 0.4 +/- 0.1 ml, P < 0.01). No significa nt differences were found between children with premature thelarche an d the control group. As a diagnostic method for the early detection of central precocious puberty, ultrasound measurement of uterine volume had a sensitivity and specificity of 100% (cut-off value, 1.8 ml), whi le ultrasound determination of ovarian volume had a sensitivity of 82% and a specificity of 95% (cutoff value, 1.2 ml). In contrast, as a di agnostic criterion the ratio of levels of luteinizing hormone to folli cle-stimulating hormone as determined following stimulation with lutei nizing hormone releasing hormone had a sensitivity of 33% and a specif icity of 100% (cut-off value, 1.0). Conclusion: ultrasonographic measu rement of uterine and ovarian volume offers a reliable means of distin guishing between isolated premature thelarche and early stages of cent ral precocious puberty.