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Clonidine suppression testing for pheochromocytoma in neurofibromatosis type 1
  1. WingYee Wan1,
  2. Bichle Nguyen1,
  3. Sky Graybill2 and
  4. Jonathan Kim1
  1. 1 Internal Medicine, Brooke Army Medical Center, Fort Sam Houston, Texas, USA
  2. 2 Endocrinology Department, Brooke Army Medical Center, Fort Sam Houston, Texas, USA
  1. Correspondence to Dr WingYee Wan,{at}


Compared with the general population, rates of pheochromocytoma are higher in neurofibromatosis type 1 (NF1) patients. However, pheochromocytoma testing is often plagued by false positive results. Here we present a patient with NF1, elevated urinary metanephrine levels, and an indeterminate adrenal nodule. Clonidine suppression testing aided diagnosis and led to definitive surgical treatment that confirmed a pheochromocytoma. Pheochromocytoma screening and clonidine suppression testing can both aid in the evaluation for catecholamine-secreting tumours.

  • adrenal disorders
  • neuro genetics
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  • Contributors BN wrote the initial draft manuscript, JK provided guidance regarding content, WW revised the manuscript and rewrote multiple drafts for final publication, and SG was the attending supervisor who oversaw the process in entirety.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Patient consent for publication Obtained.

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