The Various Etiologies of Ovarian Cysts in Prepubertal Girls

Hormonal Activation or Interaction
Central Pituitary Involvement: Transient or Persistent Activation?
Small asymptomatic cysts are a common finding in young girls. Large cysts, although less common, may not always be associated with abnormal sexual development. Occasionally, these cysts may enlarge and continue to produce estrogen, resulting in pubertal development. The incidence of ovarian cysts is very low, <5% in females between birth and age 8, and small cysts are more frequent than large cysts. In a retrospective analysis [18], 1,818 ultrasound studies in prepubertal girls were examined: only 99 patients (4.5%) presented ovarian cysts. Small cysts of <10mm (average 2–3 mm) were found in 82 of these patients (83%), large cysts of >20mm were found in 17, and only 5 of these 17 patients presented pubertal development. The onset of pubertal signs can be transient, with breast development increasing during ovarian cyst formation and decreasing with spontaneous resolution. Unilocular cysts <50mm may be followed conservatively with ultrasonography until regression. The risk of torsion increases with a diameter >50mm and with rapid progression.

On the other hand, in premature thelarche, FSH-predominant pulses induced an increased prevalence (two- to three-fold) of detectable ovarian microcysts of small diameter, <10mm.

Therefore, when larger cysts are due to persistent precocious puberty, ultrasonographic measurement of uterine and ovarian volume offers a reliable means of distinguishing between isolated premature thelarche and central precocious puberty. In a review of 26 girls with ovarian cysts, Towne et al. reported that only 4 of the 26 presented persistent isosexual puberty.

In precocious puberty, clinical signs such as breast development and pubic pilosity, accelerated growth velocity and advanced bone maturation are evident. This situation is rare and the ovarian cyst must be removed, with hormonal investigations programmed a few weeks later to evaluate hormonal status and differentiate between transient pseudopuberty, which is generally gonadotropin-independent, and true onset of central precocious puberty. These investigations associate an LHRH test and sampling for estradiol measurement. At the present time, if the hormonal results confirm the onset of central pubertal activity with an LH peak after LHRH stimulation, we propose cerebral pituitary MRI and treatment with GnRH analogue.

Pseudopuberty due to an Autonomous Cyst
McCune-Albright Syndrome. The best known type of precocious pseudopuberty with recurrent ovarian cysts is McCune-Albright syndrome, which occurs in early childhood. It is manifested by metrorrhagia and rapid breast development in small girls between 2 and 5 years. On questioning, it is not rare to learn of an identical but briefer episode in the preceding months. Pelvic ultrasonography establishes the diagnosis by identifying an ovarian cyst and signs of estrogen impregnation of the uterus. This is peripheral or pseudopuberty, which is confirmed by hormone measurements (elevated estradiol, undetectable LH and FSH levels which do not react to an LHRH test). These cystic lesions may persist, exposing the child to recurrent metrorrhagia; they may also resorb within a few weeks or become complicated by adnexal torsion or hemorrhage.