Clinical_Rounds_in_Endocrinology_Volume_II_-_Pediatric_Endocrinology

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20. A 3-year-old girl was noticed to have nonprogressive breast development by
    her mother. On evaluation, she did not have pubarche and had normal growth
    velocity without any advancement in bone age. How to proceed?
    In the index patient, the likely clinical diagnosis is isolated premature thelarche
    because it is nonprogressive, growth velocity is normal, and there is no advance-
    ment in bone age. The differences between isolated premature thelarche, and the-
    larche associated with GDPP and GIPP are described in the table given below.

Parameters

Isolated premature

thelarche

Thelarche due

to GDPP

Thelarche due to

GIPP

Age of

presentation

Usually <2 years 0–8 years 0–8 years

Breast

development

(Tanner stage)

Usually ≤ B 3 B 2 –B 5 B 2 –B 5

Other secondary

sexual

characteristics

Absent May appear May appear

Growth velocity Normal for age Increased Increased

Bone age Normal Advanced Advanced

Serum estradiol

levels

Usually within

prepubertal range, but

may be modestly elevated

Elevated Elevated

Serum FSH Prepubertal/modestly

elevated

Pubertal Prepubertal

LH response to

GnRH

Prepubertal Pubertal Prepubertal

Ovarian volume Prepubertal (<1.6 ml) Increased

(>2.8 ml)

Increased (unilateral/

bilateral)

Uterine length Prepubertal (<3.5 cm) >3.5 cm

endometrial echo

may be present

>3.5 cm endometrial echo

may be present

Parents should be reassured as isolated premature thelarche is benign and

nonprogressive, and usually regresses within 6 months to 6 years. Further, final

adult height and subsequent pubertal development are normal in these girls;

therefore, it does not require any treatment. However, regular surveillance is

required as 10 % of girls with isolated premature thelarche who have onset of

thelarche after 2 years of age may have underlying GDPP as a cause of prema-

ture thelarche.

21. What are the mechanisms proposed for the development of isolated premature
    thelarche?
    The precise cause for isolated premature thelarche is not known. The various
    proposed mechanisms include transient activation of HPG-axis with predominant

6 Precocious Puberty