Endocrine Abstracts

Growth hormone (GH) excess is extremely rare in children. It can be associated with endocrine syndromes including MEN1, Carney complex and Mc Cune Albright syndrome. We describe two cases of GH excess and their management. Patient A (15yr M) presented with fibrous dysplasia affecting his cranium and a large café-au-lait spot covering his right scapula. His height was 193cm (2.6 SDS) and BMI 29.6kg/m2(2.3SDS). His IGF1 was 84.1nmol/L (22.5 – 65.9) and GH did not suppress during an oral glucose tolerance test (OGTT) (GH nadir 1.43ug/L). Skeletal survey showed no other bony lesions. MRI of the pituitary was normal. Ophthalmology showed no effect on optic nerve or visual fields. Patient B (15M) had an antenatal diagnosis of a PRKAR1A gene change consistent with Carney Complex. Puberty commenced aged 10 years. Height SDS increased from 1SDS to 2.8SDS. GH did not suppress on OGTT (GH nadir 3.18ug/L), and IGF-I was 55.9nmol/L. Both children were discussed within the Merseyside pituitary MDT and with colleagues nationally. Treatment options including watchful wait, somatostatin analogues, GH antagonists, radiotherapy and pituitary surgery were discussed. Both patients commenced treatment with Lanreotide®, a somatostatin analogue. Patient A commenced medical therapy immediately as it has been reported that growth of fibrous dysplasia lesions slow or stop. However, shrinkage is not described. His IGF1 reduced from 131nmol/L to 96nmol/L after commencing treatment. Patient B initially underwent a period of observation. However, the pituitary adenoma increased in size (baseline 9x13x7mm vs 14x18x15mm) and medical therapy was commenced. After six months, the adenoma measured 10x14x6mm, IGF1 concentrations and height velocity have plateaued. His HbA1c is 43 mmol/mol/L (20 – 42 mmol/mol). Both patients tolerated treatment well. GH secreting tumours are rare in childhood. It has been described that somatostatin analogues may cause tumour shrinkage but are not always associated with a fall in IGF1. Patient B may still require further treatment. GH antagonists are rarely used in children and little data are available regarding their use. Pituitary surgery comes with possible life changing complications and multiple pituitary hormone deficiencies. Remission rate is not 100%.