Utility of breast ultrasonography in the diagnostic work-up of precocious puberty and proposal of a prognostic index for identifying girls with rapidly progressive central precocious puberty.

OBJECTIVE: To determine the utility of breast ultrasono- graphy in the diagnostic work-up of precocious puberty and to create a prognostic index for early differentiation between non/slowly progressive or transient forms of precocious puberty and rapidly progressive central precocious puberty.

METHODS: We recruited consecutively 60 girls with precocious pubertal development. In all the girls we evaluated Tanner stage, basal and gonadotropin-releasing hormone (GnRH)-stimulated follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, estradiol (E2) levels, and bone age, and performed pelvis and breast ultrasound examinations. Logistic regression models were fitted to identify possible diagnostic factors for rapidly progressive central precocious puberty and non/slowly progressive or transient forms.

RESULTS: Ultrasound breast volume>or=0.85 cm3 was associated with rapidly progressive central precocious puberty (P=0.01). Uterine volume>or=5 cm3, LH peak>or=7 IU/L, presence of an endometrial echo, E2 levels>or=50 pmol/L and bone age>2 SD above expected were significantly associated with rapidly progressive central precocious puberty. A multivariate model including uterine volume, E2 level, bone age, presence of an endometrial echo and ultrasound breast volume revealed a strong ability to classify rapidly progressive forms. From this multivariate analysis a prognostic index for rapidly progressive central precocious puberty was defined.

CONCLUSIONS: Ultrasound imaging allows better definition of the breast and the maturation stage than does use of Tanner's stages. Ultrasound breast volume>or=0.85 cm3 is an independent predicting factor of rapidly progressive central precocious puberty. A prognostic index that was created from a multivariate model including uterine volume, E2 level, presence of an endometrial echo, bone age and ultrasonographically determined breast volume, may help in the early differentiation between rapidly progressive central precocious puberty and non/slowly progressive or transient forms.