Gigantism and acromegaly are conditions of uncontrolled hypersecretion of growth hormone (GH) with associated excessive liver IGF1 production. 1. Over 90% are due to pituitary somatotroph adenomas, 70% of which are macroadenomas at diagnosis1. We report a case of continued GH excess of unknown source despite extensive imaging.
A 31yo recent Nepalese migrant presented with typical features of acromegaly. He was 30cm taller than his primary relatives and continued growth into his 20s, with a increase in shoe size in the last decade. On examination he was 191cm, 95kg (BMI 26kg/m2) normotensive, with gapped teeth, macroglossia, acral prominence and large hands.
IGF1 and GH were elevated (IGF1 64-83nmol/L NR: 11-32nmol/L; GH 29mIU/L NR: 0-7mIU/L) and failed to suppress on GH 75g glucose challenge test (GH 23-25mIU/L NR: < 1). Pituitary panel revealed emerging panhypopituitarism (Testosterone 1.7 NR: 8.3-30.2nmol/L, LH 2 NR: 1-10IU/L, FSH 5 NR: 1-10IU/L, TSH 2.62 NR: 0.50-4mIU/L, T4 8.6 NR: 10-19pmol/L, ACTH 4.8 NR < 20pmol/L, cortisol 192 NR: 145-619nmol/L). Contrast enhanced pituitary MRI demonstrated an enlarged bony sella with a rim of normally enhancing pituitary tissue, an inferiorly displaced optic chiasm, a sella defect and a small focus of enhancing tissue in the cavernous sinus. Neither CXR nor Ga 68-DOTATATE suggested an ectopic source.
As the complete clinical picture suggested the possibility of involution and/or infarction of a sizeable pituitary lesion which had caused bony abnormalities, the patient will be imminently undergoing trans-sphenoidal surgical exploration. Sperm cryopreservation has been completed. Intra-operative imaging and post-operative results will be available by the time of the conference and will be discussed in the context of the eight other reported cases of lesions found on surgical exploration not visible on MRI2-4. Medical management with somatostatin analogue therapy, hormone replacement, and fertility assistance will be initiated post-operatively if required.