TH1.13 The Role of Metanephrines in the Diagnosis of Pheochromocytoma

Abstract

Abstract Introduction Pheochromocytomas are rare neuroendocrine catecholamine-producing tumors that arise from either the adrenal medulla (PHEO) or extra-adrenal paraganglionic tissues (paraganglioma/PGLs). PHEO is responsible for about 0.01–0.1% of the cases of hypertension. Assessment of the plasma/urinary levels of metanephrines (catecholamines metabolites) is now considered the gold standard for the diagnosis of PHEOs. In this study, we aimed to investigate the role of the plasma and 24-hour urinary metanephrines levels in the diagnosis of PHEO/PGLs. Patients and Methods Retrospective review of 26 patients diagnosed with PHEO/PGLs. We measured the plasma/ 24-h urinary metanephrines. The data were compared with another set of 26 patients with other adrenal pathologies. The correlation coefficient between the tumor sizes and the plasma/24-hour urinary metanephrines levels was calculated. Results The mean tumor size was 4.88 ± 1.99 cm. The sensitivity and specificity of the plasma metanephrines were about 95.8% and 98%, respectively, while for 24-hour urinary metanephrines were about 83.3% and 98%, respectively. We found a strong positive relationship (r = 0.472, P = 0.05) between the tumor size and the summed plasma concentrations of metanephrines. The relation between the tumor diameter and summed 24-hour urinary metanephrine was potentially strong (r = 0.354, P = 0. 083). Conclusion Plasma/24-hour urinary metanephrines are of great value in the diagnosis PHEOs/ PGLs as they are continuously produced by the tumor. There are strong relations between the size of these tumors and the plasma and urinary concentration of these metabolites, which can help to predict the size of the tumor even before imaging.