ESPE Abstracts

Background: Acromegaly is a rare childhood disorder. The use of a growth hormone (GH) receptor antagonist, pegvisomant, has shown great results in adults with acromegaly. We describe results of pegvisomant therapy in two girls with invasive GH pituitary macroadenomas.

Case presentation: Case 1: A somatotroph pituitary macroadenoma was diagnosed in a 8-year-old girl with progressive tall stature (height: 148 cm, >+3 S.D.; growth velocity (GV):11 cm/year), GH hypersecretion without suppression during oral glucose loading (nadir serum GH: 34 mU/l), high serum IGF1 (691 ng/ml) and prolactin (270 mUI/l) levels. Bone age was 10 years. Transphenoidal surgical tumor removal was incomplete. Histological examination showed a mixed GH and prolactin-secreting adenoma. Serum IGF1 and GH levels remain high after surgery and cabergoline treatment (819 ng/ml, 20 mUI/l). Pegvisomant in combination with cabergoline quickly led to IGF1 normalisation (115 ng/ml) and growth arrest (GV: 0 cm/7 months). Case 2: A 15-year-old girl presented with clinical and biochemical evidence of acromegaly: tall stature (182 cm, >3 S.D., no GV available), pubertal stage IV, bone age 13 years, high IGF1 and GH serum levels (776 ng/ml, 109 mUI/l). Pituitary MRI revealed a large and invasive mass. She was treated with a combination of oestrogen -to accelerate epiphyseal fusion-, somatostatin analogs and pegvisomant titrated up to 40 mg/day. Medical treatment failed to normalize IGF1 and halt growth (GV:2 cm/6 months) but major weight gain was noticed (+14 kg/6 months). Therefore the tumour was partially resected by a trans-sphenoidal surgical approach. Histological characterization confirmed the diagnosis of GH-secreting adenoma. Pegvisomant adjuvant therapy was resumed to improve IGF1 serum level control (571 ng/ml after surgery and nadir GH: 8.7 mU/l) and halt physical growth.

Conclusion: In childhood acromegaly, pegvisomant appears to be effective in stunting growth and normalizing IGF1 only after pituitary tumor debulking.