Poster Presentation Asia Pacific Neuroendocrine Tumour Society 2018

Ectopic Acromegaly due to GHRH-secreting Bronchial Tumour (#118)

Winnie Ho 1 2 , Amy Harding 2 3 , Rahul Barmanray 4 , James King 5 , Rosemary Wong 6 , Christopher Yates 2 3 , Dev Kevat 4 7
  1. Endocrinology, Bendigo Health, Bendigo, VIC, Australia
  2. Endocrinology , Western Health, Melbourne, VIC, Australia
  3. Endocrinology, Melbourne Health, Melbourne, VIC, Australia
  4. Endocrinology , Western Health, Melbourne, VIC, Australia
  5. Neurosurgery, Royal Melbourne Hospital, Melbourne, Victoria, Australia
  6. Endocrinology, Eastern Health, Melbourne, Victoria, Australia
  7. Medicine, Monash University , Melbourne, VIC, Australia

Case presentation:

A 59-year-old ex-smoker presented with abdominal pain and constipation.  Acromegalic features were noted, with history revealing facial coarsening and acral enlargement over a 5-year period. His growth hormone failed to suppress after 75g oral glucose and his IGF-1 level was six times the upper limit of normal. An MRI revealed pituitary enlargement. X-rays and CT chest revealed a 5x7x6cm left perihilar mass. FDG PET/CT demonstrated FDG avidity in the perihilar mass, pituitary and right lower thyroid pole. Ga-68 DOTATATE PET/CT demonstrated somatostatin receptor activity within the lung mass and the pituitary.  Thyroid ultrasound revealed a multinodular goitre, with a benign aspiration result from the dominant nodule.

The patient underwent a left pneumonectomy, with histology confirming a Growth Hormone Releasing Hormone (GHRH) secreting carcinoid tumour; 0/18 lymph nodes were involved.   Postoperatively, acromegalic features improved, serum GHRH was normal and MRI showed a reduction in pituitary size, however, GH and IGF-1 remained elevated. Repeat CT chest revealed an enhancing left thoracic cavity soft tissue lesion. The patient is being assessed for recurrent carcinoid and the development of a somatotrophinoma.  Genetic testing for Multiple Endocrine Neoplasia 1 and 4 was negative.

Discussion:

Ectopic GHRH secretion is responsible for <1% of cases of acromegaly [1]. The majority of these cases are due to bronchial carcinoid tumours and pancreatic neuroendocrine tumours, which are both associated with MEN-1[1-3]. Pituitary hyperplasia resulting from GHRH hypersecretion develops in up to 60% of cases and may be indistinguishable from an adenoma [1].  Suspicion for ectopic acromegaly arises when there is discordance between features of acromegaly and MRI pituitary. Plasma GHRH determination is useful as elevated levels have been found in all cases of ectopic GHRH-secreting tumours, but not found in patients with somatotroph adenomas (2,4). Complete tumour resection is the only curative treatment for ectopic acromegaly.

 

 5b7284f15187e-Fig+1+-+MRI+pituitary.png

5b7284f15187e-Fig+2+-+CT+chest.png

5b7286bb9407c-Fig+3+-+PET+scan.png 5b7284f15187e-Fig+4+-+Dotatate+scan.png

 

 

  1. Borson-Chazot, F., et al., Acromegaly induced by ectopic secretion of GHRH: a review 30 years after GHRH discovery. Ann Endocrinol (Paris), 2012. 73(6): p. 497-502.
  2. Garby, L., et al., Clinical characteristics and outcome of acromegaly induced by ectopic secretion of growth hormone-releasing hormone (GHRH): a French nationwide series of 21 cases. J Clin Endocrinol Metab, 2012. 97(6): p. 2093-104.
  3. Van den Bruel, A., et al., Hormonal and volumetric long term control of a growth hormone-releasing hormone-producing carcinoid tumor. J Clin Endocrinol Metab, 1999. 84(9): p. 3162-9.
  4. Thorner MO, Frohman LA, Leong DA, Thominet J, Downs T, Hellmann P, Chitwood J, Vaughan JM, Vale W 1984 Extrahypothalamic growth-hormone-releasing factor (GRF) secretion is a rare cause of acromegaly: plasma GRF levels in 177 acromegalic patients. J Clin Endocrinol Metab 59:846 – 849