ESA-SRB-AOTA 2019

Tumour localisation of phaeochromocytoma or paraganglioma based on plasma metanephrines (#554)

Danielle Tu 1 , Hamish Russell 1
  1. Diabetes and Endocrinology, Liverpool Hospital, Liverpool, NSW , Australia

Background

Phaeochromocytomas (PHE) and paragangliomas (PPL) are rare catecholamine-producing neuroendocrine tumours that arise from chromaffin cells within or outside of the adrenals respectively.1 Based on previous observations, PPL predominantly secrete noradrenaline (noradrenergic phenotype) while adrenaline-secreting (adrenergic phenotype) tumours are usually confined to the adrenals.1-3 Further studies indicate that half of PHE have an adrenergic phenotype while the other half produce a variable mixture of adrenaline and noradrenaline.1-4 Patterns of increases in their metabolites can help predict tumour location.1,2 Significant elevations in metanephrines are invariably due to an adrenal tumour.1,2 Although isolated increases in normetanephrine cannot predict tumour location, when accompanied with a considerable rise in methoxy-tyramine, the tumour is almost always extra-adrenal.1

 

Methods

We analysed plasma metanephrines of 20 patients with PHE or PPL and determined their phenotype by calculating the percentage increase of plasma metanephrines. An increase in plasma free metanephrines >10% of the combined increases in normetanephrines and metanephrines were consistent with an adrenergic phenotype while negligible increases <10% were consistent with a noradrenergic phenotype.2    

 

Results

13 out of 20 patients were diagnosed with PHE. 6 out of 13 (46%) patients with PHE have an adrenergic phenotype and the other 7 (54%) patients presented with a noradrenergic phenotype. 6 of 7 (86%) patients with PPL have a noradrenergic phenotype. 

 

Conclusion

Measurement of plasma metanephrines not only assist in diagnosing PHE and PPL, but can help predict its location. Our results are consistent with the current literature.

  1. Eisenhofer G and Peitzsch M. Laboratory evaluation of pheochromocytoma and paraganglioma. Clin Chem. 2014; 60(12): 1486-99.
  2. Eisenhofer G, Lenders JW, Goldstein DS et al. Pheochromocytoma catecholamine phenotypes and prediction of tumour size and location by use of plasma free metanephrines. Clin Chem. 2005; 51(4): 735-44.
  3. van der Harst E, de Herder WW, de Krijger RR et al. The value of plasma markers for the clinical behaviour of phaeochromocytomas. Eur J Endocrinol. 2002; 147(1): 85-94.
  4. Kimura N, Miura Y, Nagatsu I et al. Catecholamine synthesizing enzymes in 70 cases of functioning and non-functioning phaeochromocyttoma and extra-adrenal paraganglioma. Virchows Arch A Pathol Anat Histopathol. 1992; 421(1): 25-32.