ESPE Abstracts

Background: McCune–Albright Syndrome is a combination of polyostotic fibrous dysplasia (BFD), café’-au-lait skin pigmentation and hyperfunctioning endocrinopathies. It results from postzygotic mutations in a-subunit of the Gsalfa protein and the consequent phenotype is a mosaic with high degree of clinical variability.

Objective and hypotheses: The aim of the study is determine prevalence and characteristics of GH hypersecretion (GHH) in MAS.

Method: 31/142 (21.8%) patients with GHH are identified. In all we study auxological data, biochemical GHH (IGF1 Z-score, random GH, GH after OGTT), association with prolactine hypersecretion (PH), possible abnormal pituitary MRI, BFD, other endocrinopathies and response to medical and other treatment.

Results: Average age at diagnosis is 13.9 y.o. (from 3 to 36). Male are 18/31 (58%), female are 13/31 (42%). PH occurs in 27/31 (87%). Pituitary adenoma is evidenced in 16/31 (52%), while craniofacial and long bone FD are evidenced in 100%. Medical treatment was performed in 25/31: in 17 ocreotide 10–30 mg i.m./month, in 5 ocreotide 30 mg i.m./month and pegvisomant 20 mg s.c./day, in 1 ocreotide 30 mg i.m./month, pegvisomant 20 mg s.c./day and pipuitary irradiation, in 2 ocreotide 30 mg i.m./month and transphenoidal pituitary surgery (one died for post-operative complications). 19/24 (79%) have complete control of GHH (−2 <IGF1 Z-score< +2), three patients are non-compliant to therapy.

Conclusion: GHH can occur from childhood to adulthood above in 20% of MAS patients and when present is always associated with BFD. Micro or macro-adenoma is evidenced only in half of cases because the pituitary gland is often diffusely involved with areas of somatotroph hyperplasia. Medical therapy (ocreotide and pegvisomant) realize a good control of disease that is important to prevent a higher risk of BFD morbidity. Pituitary surgeon and irradiation are respectively the second and the third options due to thickness of BFD, post-operative complications and possible malignant transformation of BFD.