title: Gigantism due to growth hormone excess in a boy with optic glioma.
abstract: True gigantism is rare in early childhood and is usually due to excess GH secretion from a pituitary adenoma. We report a case in which the endocrine abnormality is secondary to an optic glioma. Careful endocrine evaluation has shown that GH peak amplitude was not increased but rather there was failure of GH levels to suppress to baseline and a lack of pulsatility. There is no evidence of a direct secretory role for the tumour and we postulate that the tumour is affecting GH secretion through an effect on somatostatin tone. Specific tumour therapy is not indicated for this patient in the absence of mass effect or visual disturbance. The GH excess is being treated with somatostatin analogue (Octreotide) and as he has developed precocious puberty he is also receiving long acting GnRH analogue (Zoladex). This boy appears likely to have neurofibromatosis type 1 (NF1) which raises the question of subtle GH excess in NF1 patients with tall stature.
authors.affiliation: Department of Child Health, Royal Hospital for Sick Children, Glasgow, UK.
authors.forename: F M
authors.initials: FM
authors.lastname: Drimmie
authors.forename: A C
authors.initials: AC
authors.lastname: MacLennan
authors.forename: J A
authors.initials: JA
authors.lastname: Nicoll
authors.forename: E
authors.initials: E
authors.lastname: Simpson
authors.forename: E
authors.initials: E
authors.lastname: McNeill
authors.forename: M D
authors.initials: MD
authors.lastname: Donaldson
mesh_terms: D000328:Adult; D002675:Child, Preschool; D005877:Gigantism / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives; D017273:Goserelin / Q000627:therapeutic use; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009456:Neurofibromatosis 1 / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy; D015282:Octreotide / Q000627:therapeutic use; D020339:Optic Nerve Glioma / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D011629:Puberty, Precocious / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy; D013004:Somatostatin / Q000031:analogs & derivatives
chemical_list: D017273:Goserelin; D007987:Gonadotropin-Releasing Hormone; D013004:Somatostatin; D013006:Growth Hormone; D015282:Octreotide