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Premature Thelarche

Xuemin SUN, Surgeon


Premature thelarche — Most cases of premature thelarche are idiopathic and present under two years of age (and may even start at birth). Many cases will remit spontaneously, and most others do not progress. However, follow-up is warranted because premature thelarche can represent the initial presentation of true central precocious puberty(CPP)in 10 to 20 percent of children referred to pediatric endocrine units .

Key features of premature thelarche are:

  • Isolated breast development, either unilateral or bilateral – Typically not developing beyond Tanner stage 3
  • Absence of other secondary sexual characteristics
  • Normal height velocity for age (not accelerated)
  • Normal or near-normal bone age

Serum luteinizing hormone (LH) and estradiol concentrations are typically in the prepubertal range, but one should be cautious in interpreting these levels in children under the age of two years because elevations can be seen as part of the normal transient “mini-puberty of infancy,” and CPP can be diagnosed inappropriately .

Toddlers and children — Premature thelarche occurs in two peaks: one during the first two years of life and the other at six to eight years of age [83], with potentially different underlying pathophysiology accountable for each of these peaks. Postulated mechanisms include transient activation of the hypothalamic-pituitary-gonadal axis with excess follicle-stimulating hormone (FSH) secretion [84]. In infants, soy-based formulas have been implicated, although the evidence is weak and may represent only a slower waning of breast tissue during infancy . Use of lavender oil, tea tree oil, or hair care products that contain placental extract has also been implicated in some cases of premature thelarche. In most instances, no cause can be found.

In most cases, premature thelarche requires only reassurance. However, the patient should be examined for other signs of pubertal development, and growth data should be plotted; an accelerated height velocity may be indicative of progressive puberty and requires further evaluation. To identify patients with progressive puberty, patients should be monitored for several months for evidence of pubertal progression.