ESPE Abstracts

Background: Simple clinical investigations to differ harmless premature thelarche (PT) from pubertal precocity and other pathological conditions are needed as PT is a common condition in girls under the age of 3–4 year.

Objective and hypotheses: Since 17β-oestradiol (17β-E2) is the major driver of breast development, the hypothesis is, that it is possible to define an upper serum 17β-oestradiol (17β-E2) level for harmless PT in girls under the age of 4 year.

Method: All determinations of 17β-E2 in West Sweden are sent to Gothenburg Pediatric Growth Research Center Laboratory (GP-GRC) as this is the only laboratory that can analyse paediatric 17β-E2 levels (using a high sensitive extraction RIA). Together with the result of the 17β-E2 levels there was sent to the responsible paediatrician a request to ask the parents for participation in a study on evaluation of the clinical outcome of PT. Two standard-deviations (SD) above the mean for girls with benign PT was considered as the upper limit for serum 17β-E2 for harmless PT.

Results: Totally 236 17β-E2 serum analyses were made for girls (age 1–48 months) with Tanner breast stage 2–3 during the 10-year study period. 129 of these patients participated in the follow up study on evaluation of clinical outcome of PT. In the follow up study 125 of 129 girls had a benign PT and their mean serum 17β-E2 level was 15 pmol/l with an SD of 8 pmol/l. The mean serum 17β-E2 plus 2SD was 32 pmol/l and considered as an upper limit for serum 17β-E2 in girls with benign PT. All five girls with harmful PT had17β-E2-levels above 70 pmol/l.

Conclusion: This is the first study to define an upper 17β-E2 level that is associated with benign PT, 17β-E2 levels below 32 pmol/l is associated with benign form of PT. Support are concomitant serum LH levels under the detection limit, determined with IRMA methods.

Funding: This work was financially supported by grants from the Swedish Medical Research Council, LUA/ALF and regionala grants from NÄL/VG.