Endocrine Abstracts

Despite rarer in children than in adults, GH-secreting pituitary adenomas are often more aggressive, being challenging cases during childhood. Somatic changes (tall stature and acromegalic features), optic chiasma syndrome or metabolic and cardiovascular impact of GH excess trigger diagnosis and requires aggressive management. Treatment options are surgery, radiotherapy and medical therapy using somatostatin analogues, dopamine agonists and recently, GH receptor antagonists – Pegvisomant, all with pro and cons.

A girl aged 12 was admitted for cavernous sinus syndrome due to an aggressive pituitary adenoma. She was submitted twice to pituitary surgery at 3 months interval (Jan and Apr 2007), with partial tumor removal, immediately followed by γ knife radiosurgery. Despite signs were not suggestive for GH secretion, immunohistochemistry proved intense GH secretion. GH and IGF1 values certified autonomous GH secretion. She underwent a third surgery in Erlangen, Germany (Sep 2007), with a forth re-intervention in the same center in Jan 2008, with efficient debulking of suprachiasmatic extension, but remnants in the cavernous sinuses. In the same time, since Oct 2007 she started SMSa Lanreotide, initially at 60, then at 90 mg/month, with poor response (nadir GH=66 ng/ml), to which Cabergoline 3 mg/week was added since May 2009. In Sep 2008, she underwent fractionated additional stereotaxic radiotherapy in Erlangen, in the area of cavernous sinuses extension.

At the last admission (June 2009) the patient aged 16-year-old was 180 cm height, 66.5 kg and had only discreet facial acromegalic features. Pubertal development was Tanner stage B2P4. GH hypersecretion was demonstrated with very high levels of serum GH without suppression during OGTT (nadir serum GH 61.4 ng/ml) and increased serum IGF I (970 ng/ml, normal range for age 163–584 ng/ml). The thyroid hormones and cortisol tests was normal but she had hypogonadotropic hypogonadism. Pituitary MRI scan showed an intrasellar tumor mass with invasion of cavernous sinuses and retrosellar extension. Ophtalmologic examination revealed normal bilateral visual field but paresis of right common oculomotor nerve, while hearth evaluation showed signs of acromegalic cardiomiopathy. She was treated with Cabergoline 3 mg/week and estradiol 1 mg/day for induction of puberty. At this time, due to the aggressive tumor and the lack of control of tumor secretion using extensive surgery, radiotherapy and high doses of somatostatin analogues, GH receptor antagonists therapy was considered. The patient started treatment with Pegvisomant 10 mg/day, well tolerated, without side effects. However, pro and cons concerning radiotherapy and extensive surgery, timing and availability of use of expensive drugs, represent challenges for management in which fight against tumor must be balanced against a life-long preservation of pituitary function and visual pathway in a young patient.

The use of Pegvisomant has shown great promise in adults with acromegaly, but experience in pediatric patients is lacking. In our patient a close follow-up is necessary.