Title:Premature Thelarche: An Updated Review
Volume: 20
Issue: 4
Author(s): Alexander K.C. Leung*, Joseph M. Lam and Kam L. Hon
Affiliation:
- Department of Pediatrics, The University of Calgary, Alberta Children's Hospital, Calgary, Alberta, Canada
Keywords:
Breast enlargement, estrogen exposure, parental reassurance, premature puberty, precocious puberty, premature thelarche.
Abstract:
Background: Premature thelarche is the most common pubertal disorder in girls. The
condition should be differentiated from central precocious puberty which may result in early epiphyseal
fusion and reduced adult height, necessitating treatment.
Objectives: The purpose of this article is to familiarize physicians with the clinical manifestations of
premature thelarche and laboratory tests that may help distinguish premature thelarche from central
precocious puberty.
Methods: A search was conducted in September 2022 in PubMed Clinical Queries using the key
term "Premature thelarche". The search strategy included all clinical trials, observational studies,
and reviews published within the past 10 years. Only papers published in the English literature were
included in this review. The information retrieved from the above search was used to compile the
present article.
Results: Premature thelarche denotes isolated breast development before the age of 8 years in girls
who do not manifest other signs of pubertal development. The condition is especially prevalent during
the first two years of life. The majority of cases of premature thelarche are idiopathic. The condition
may result from an unsuppressed hypothalamic-pituitary-gonadal axis in the early years of
life, an "overactivation" of the hypothalamic-pituitary axis in early childhood secondary to altered
sensitivity to steroids of the hypothalamic receptors controlling sexual maturation, increased circulating
free estradiol, increased sensitivity of breast tissue to estrogens, and exposure to exogenous
estrogens. The cardinal feature of premature thelarche is breast development which occurs without
additional signs of pubertal development in girls under 8 years of age. The enlargement may involve
only one breast, both breasts asymmetrically, or both breasts symmetrically. The breast size
may fluctuate cyclically. The enlarged breast tissue may be transiently tender. There should be no
significant changes in the nipples or areolae and no pubic or axillary hair. The vulva, labia majora,
labia minora, and vagina remain prepubertal. Affected girls have a childlike body habitus and do not
have mature contours. They are of average height and weight. Growth and osseous maturation, the
onset of puberty and menarche, and the pattern of adolescent sexual development remain normal.
Most cases of premature thelarche can be diagnosed on clinical grounds. Laboratory tests are seldom
indicated. No single test can reliably differentiate premature thelarche from precocious puberty.
Conclusion: Premature thelarche is benign, and no therapy is necessary apart from parental reassurance.
As enlargement of breasts may be the first sign of central precocious puberty, a prolonged follow-
up period every 3 to 6 months with close monitoring of other pubertal events and linear growth
is indicated in all instances.
