Thelarche – Current Opinions

Isolated premature mammary gland enlargement, or precocious thelarche (thelarche praecox, t.p.), is a glandular tissue development which occurs in girls below eight years of age without any other symptoms of systemic estro− gen activity. T.p. is usually observed during the first two to three years of life. Ethnic and nutritional factors influ− ence the frequency of t.p. incidence. T.p. is connected with endogenous and exogenous factors. Early stages in the activation of the hypothalamic−pituitary−ovarian axis, activating GNAS1 gene mutation, and FSH receptor poly− morphism are the most frequently mentioned endogenous factors. It has been suggested that exposure to estrogenic disrupters, such as dioxins, furans, organic halogens, and phthalates, can cause t.p. epidemics in some geographi− cal areas. FSH levels, both basal and GnRHa stimulated, are significantly higher in t.p. girls than in their peers. The concentrations of inhibin B, leptin, and IGF1 in t.p. patients are in between those of the prepubertal and pubertal periods. Visual examinations, such as pituitary gland MR and breast and pelvic ultrasound, are also useful in the differential diagnose of t.p. and other disorders of puberty. Spontaneous regression of t.p. occurs from six months to six years after establishing diagnosis in most girls. However, in 14% of cases, GnRH−dependent precocious puberty develops. Continued control of the clinical state and use of available diagnostic methods in each suspicious case is essential in the care of t.p. patients (Adv Clin Exp Med 2007, 16, 2, 329–334).