Endocrine Abstracts

A 24 year old male presented to his GP with rapid growth in height and joint pain and a physiotherapist suggested that he could have late stage gigantism. Upon presentation he had recently grown from 208 cm to 216 cm tall during a short number of months. His symptoms included fatigue, sweating, oily skin and deepening of his voice. Of note he had prognathism, frontal bossing, macroglossia, broadening of his nose and significant interdental spacing. His mother is 165 cm tall, his father is 172 cm tall. His paternal uncle is 188 cm tall and reportedly his paternal grandfather was over 183 cm tall. Interestingly he has an identical twin who is only 185 cm tall and wears shoes 6 sizes smaller than the patient. Childhood photos confirm that they are indeed identical twins and previously only close family could tell them apart. At the age of 16 he started to grow taller, and they now look remarkably different from each other in terms of both facial features and body size. Biochemical testing revealed an IGF-1 of 698ng/mL (98.7-289) with a growth hormone >40 on OGTT, confirming growth hormone hypersecretion and a diagnosis of gigantism. In addition, he was successfully treated for LH, FSH, TSH, ACTH deficiency with supplementary medication. Genetic testing was confirmatory for MEN-1. MRI pituitary scan identified a 4.7 cm giant pituitary macrodadenoma with bilateral cavernous sinus involvement. Visual field testing showed a significant left temporal field defect. He recently underwent transsphenoidal resection of the pituitary tumour. The histology showed a bone invasive densely-granulated somatotroph pituitary neuroendocrine tumour with Ki-67 <1%. Post-operative recovery was complicated with meningitis and biochemistry on day 2 post-operation showed an IGF-1 of 586 with random GH of 15.8. However, further biochemical assessment will be required as an outpatient. This case highlights the importance of early identification and referral to specialist services. The patient reports distress that he visited his GP many times without a diagnosis or referral leading to irreversible physical changes. However, he is grateful that his family and any future offspring may be able to have genetic testing. This case raises several important discussion points including:1. Why has one identical twin developed significant pathology whilst the other remains healthy? 2. How do we diagnose such a rare condition at an earlier stage to avoid preventable ongoing harm from excess GH secretion?