Why do patients with pheochromocytomas/paragangliomas exhibit significantly inconsistent elevation of catecholamines and their metabolites? a large Chinese cohort study.

Abstract

Inconsistent elevation of catecholamines (CAs) and metanephrines (MNs) was observed in pheochromocytomas/paragangliomas (PPGLs). This study aimed to explore its potential causes and report the diagnostic efficacy of MNs and CAs in a large Chinese PPGL cohort. Clinical data and results of hormone tests were retrospectively collected. The sensitivity of plasma MNs and 24h-urinary CAs was analyzed. Clinical characteristics were compared between patients with positive and negative biochemical results, and among those with inconsistent elevation of MNs and CAs. Seven hundred and three patients were included, with a median onset age of 41.0 years. Plasma MNs (93% ~ 99%) showed prior diagnostic sensitivity to 24h-urinary CAs (74% ~ 89%). Patients with negative biochemical results presented as a smaller tumor (1.7 cm vs. 4.3 cm, P = 0.001), a higher proportion of normal blood pressure (60.0% vs. 20.5%, P = 0.002) and negative 131I-meta-iodobenzylguanidine (131I-MIBG) imaging (55.6% vs. 17.3%, P = 0.012). An earlier age of onset (40.0 vs. 41.0 vs. 44.5 years, P = 0.025), a higher proportion of paroxysmal hypertension (36.5% vs. 29.2% vs. 32.2%, P = 0.005) and the Epinephrine secretion type (79.3% vs. 37.7% vs. 48.0%, P < 0.001) were found in patients with the ratio of MNs/CAs elevation multiples <0.5 than those with the ratio between 0.5 and 2 or >2. Plasma MNs exhibited a superior sensitivity than 24-h-urinary CAs in the Chinese PPGL diagnosis. Patients with a small tumor, normal blood pressure and negative 131I-MIBG imaging were prone to express negative biochemical levels. Additionally, an obvious elevation of 24-h-urinary CAs than plasma MNs was correlated to paroxysmal hypertension and the Epinephrine type.