Differences in Body Composition in Patients with Pheochromocytomas and Age- and Sex-Matched Non-Functioning Adrenal Tumors: A Matched Cohort Study.

OBJECTIVE: Pheochromocytomas and paragangliomas (PPGLs) are associated with profound metabolic and cardiovascular alterations. Chronic catecholamine excess induces a hypermetabolic and catabolic state that may affect skeletal muscle and adipose tissue distribution, potentially contributing to metabolic comorbidities. However, data regarding body composition changes in patients with PPGLs remain limited. Thus, we aimed to evaluate body composition differences between patients with PPGLs and age- and sex-matched patients with non-functioning adrenal tumors (NFATs), and to explore their association with metabolic comorbidities. METHODS: We conducted a retrospective study including 44 patients with histologically confirmed PPGLs and 88 age- and sex-matched patients with NFATs. Contrast-enhanced computed tomography (CT) scans obtained at diagnosis were analyzed using semi-automated software enabling two-dimensional (2D) and three-dimensional (3D) body composition assessment. RESULTS: Patients with PPGLs showed significantly higher muscle-related parameters compared with NFATs, including muscle mass percentage, lean mass percentage, and muscle density in both 2D and 3D analyses (p<0.05). Conversely, adipose tissue compartments were consistently reduced in PPGLs. Intramuscualr adipose tissue (IMAT) area and index were significantly lower in the 2D analysis, with increased density (p<0.01) while IMAT volume and mass were reduced and density increased in the 3D analysis (p<0.05). Muscle quality was slightly but significantly better in the PPGLs group (p<0.01). Similarly, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) parameters, including area, volume, and mass, were significantly lower in patients with PPGLs, in both, 2D and 3D analysis (p<0.05) whereas VAT density was significantly higher (p<0.01, p<0.001 respectively). In multivariate analyses adjusted for age, sex, hormone secretion, alcohol consumption, tobacco exposure and BMI, SAT was independently associated with hypertension in the PPGL group. In contrast, several muscle- and adipose tissue-related parameters were independently associated with hypertension and impaired glucose metabolism in patients with NFATs. CONCLUSION: Patients with PPGLs exhibit a distinct body composition profile characterized by preserved muscle mass and reduced adipose tissue compartments. Despite these marked differences, body composition parameters were not independently associated with metabolic comorbidities in PPGLs, suggesting that catecholamine excess may play a predominant role in metabolic dysfunction beyond adipose tissue distribution alone.