Precocious puberty in children with tumours of the suprasellar and pineal areas: Organic central precocious puberty

During the past 11 y, 115 children younger than 8/9 y of age (female/male) with tumours of the suprasellar or pineal areas were followed in our clinic to study the incidence of precocious puberty. In addition, type of central lesion, clinical characteristics and gonadotropic secretion were studied i n order to elucidate the different mechanisms of gonadal activation. A cont rol group of 21 patients with idiopathic precocious puberty and a control g roup of 10 age-matched patients with suprasellar tumours without precocious puberty were also studied. Precocious puberty associated with organic cent ral lesions was found at diagnosis in 30 patients (26%), in 9 out of 48 pat ients with glial cell rumours (18.7%), 6 out of 9 patients with germ cell t urnouts (66.6%), 11 out of 11 patients with hypothalamic hamartomas (100%) and in 4 out of 4 patients with subarachnoid cysts or arachnoidocele (100%) . Precocious puberty was not found in any of 36 patients with craniopharyng ioma. With the exception of one patient with pineal germinoma, all lesions were localized to the suprasellar area. In all patients with hypothalamic h amartoma, precocious puberty was diagnosed before 4 y of age, while in most patients with the other lesions, it was diagnosed after this age. Height S DS, weight increase and advancement of bone age were similar in both idiopa thic and organic central precocious puberty. Maximal LH responses to GnRH i n idiopathic and organic central precocious puberty were similar except for germ cell turnouts. Patients with suprasellar turnouts without precocious puberty had lower maximal LH (but not FSH) responses to GnRH with the excep tion of germ cell turnouts. In the latter, elevation of serum beta -hCG ind icates that this gonadotropin was responsible for gonadal stimulation. In h ypothalamic hamartomas, the prepubertal hiatus in the activity of the GnRH pulse generator was absent. The mechanism of this failure in the inactivati on of GnRH is unknown. Data suggest that in glial cell turnouts and in suba rachnoid cysts, an unknown factor, probably secreted by the turnouts, advan ces the tempo of GnRH maturation. Therefore, the aetiology of organic centr al precocious puberty is multiple and is directly related to location and t ype of lesion. Conclusion: This clinical information suggests that the onset of puberty is not the result of the disruption of a putative pulse generator inhibitory influence but the consequence of secretion of stimulatory substances by the lesions.