The biological diagnosis of pheochromocytoma (P) and/or paraganglioma (Pgg) relies on the identification of excessive secretion of the metanephrines. Chomogranin A (CgA) is a general indicator of neuroendocrine tumours that is highly expressed in P and correlate with tumour mass and secretory activity. The CgA test could be indicated as a useful test in patients with false positive metanephrines results. The aim of our prospective bi-centre study, is to evaluate the performances of the CgA assay in the diagnosis of the P and Pgg according to the hereditary context and the localization of these tumours. One hundred forty six patients (67 females and 79 males) have a P and/or Pgg. All patients have had surgery and the diagnoses were confirmed by histological examinations. Thirsty eight patients (26%) have a hereditary disease.We used a radioimmunometric assay (Cis Bio-international, cut-off level to 120 ng/ml). The overall sensitivity of the CgA was equal to 92.7, 95.3% in a sporadic context and 84% in a hereditary context. The means CgA are significant different between the hereditary or sporadic diseases (P<0.01) as for the metanephrines concentrations. In patients with Pgg, (11 sporadic, 19 hereditary) the mean CgA was significant higher in the sporadic than in the hereditary Pgg (P<0.05). The means CgA in patients with sporadic P did not differ significantly from those of patients with sporadic Pgg. The means CgA appears also to be different regarding the genetic forms of P and Pgg.
In conclusion, CgA assay is a useful tool for the diagnosis of P and Pgg with a high sensitivity, better for sporadic than for hereditary diseases. CgA is a biochemical marker for the diagnosis of the P as for the majority of the Pgg with some variations according to the genetic context.
25 - 29 Apr 2009
European Society of Endocrinology