Genotype-Dependent Brown Adipose Tissue Activation in Patients With Pheochromocytoma and Paraganglioma

CONTEXT: Patients with pheochromocytomas and paragangliomas (PGLs) may have brown adipose tissue (BAT) activation induced by catecholamine excess. 18F-fluorodeoxyglucose (18F-FDG) PET/CT can be used for the localization of both PGLs and BAT. It is unknown whether BAT is specifically affected by altered cellular energy metabolism in patients with SDHx and VHL-related PGLs. OBJECTIVE: To determine endocrine and paracrine effects of catecholamine excess on BAT activation in patients with PGLS as detected by 18F-FDG PET/CT, taking into account genetic variation. DESIGN: Patients with PGLs who were fully genetically characterized underwent pre-surgical 18F-FDG PET/CT imaging for tumor localization and to quantify BAT activation. SETTING: Single Dutch tertiary referral centre. PATIENTS AND INTERVENTION: 73 patients, age 52.4 +/- 15.4 yr, BMI 25.2 +/- 4.1 kg/m2, mean +/- SD, were grouped into sporadic, cluster 1 (SDHx, VHL) and cluster 2 (RET, NF1, MAX) mutations. MAIN OUTCOME MEASURES: 18F-FDG mean standard uptake values (SUVmean) were assessed in predefined BAT locations, including perirenal fat. RESULTS: 21/73 (28.8%) patients exhibited BAT activation. BAT activation was absent in all six patients with non-secreting PGLs. No difference in 18F-FDG uptake by perirenal fat on the side of the pheochromocytoma and the contralateral side was observed (SUVmean 0.80 vs. 0.78 respectively, P=0.42). The prevalence of BAT activation did not differ between sporadic (28.9%), cluster 1 (40.0%) and cluster 2 patients (15.4%), P=0.36. CONCLUSION: Patients with PGLs exhibit a high prevalence of BAT activation on 18F-FDG PET/CT. This is likely due to systemic catecholamine excess. BAT activation is not associated with specific germline mutations