Features of Asymptomatic Pheochromocytoma/Paraganglioma Based on Clinical-Laboratory Examination and Computed Tomography

BACKGROUND: Although pheochromocytomas and paragangliomas (PPGLs) classically present with distinct clinical signs, there is a category of patients with asymptomatic disease course. Despite the absence of clinical manifestations, these patients retain the risk of life-threatening hypertensive crisis and other cardiovascular complications. The clinical, laboratory, and imaging characteristics of asymptomatic PPGLs remain insufficiently studied and are of significant scientific and practical interest.

AIM: To analyze the clinical, laboratory, and imaging characteristics of asymptomatic PPGLs compared to symptomatic ones.

MATERIALS AND METHODS: The analysis included 347 patients with histologically confirmed PPGL who underwent surgery at the Saint Petersburg State University Hospital. Retrospective analysis encompassed demographic data, medical history (primary and comorbid conditions), laboratory findings, and computed tomography (CT) data. RESULTS: The PPGLs patient cohort included 45 cases without clinical signs of catecholamine hypersecretion. The asymptomatic subgroup, compared to symptomatic patients, exhibited younger age (43 [33; 51] vs. 48 [37; 57] years); smaller maximum tumor size (34 [27; 53] vs. 45 [34; 60] mm); lower metanephrine/normetanephrine ratio (0.29 [0.10; 0.79] vs. 0.51 [0.09; 1.23]).

CT imaging revealed slightly higher radiodensity values in asymptomatic PPGLs during arterial, venous, and delayed phases compared to symptomatic tumors. However, absolute and relative washout percentages did not differ significantly.

CONCLUSION: The younger age and smaller tumor size in asymptomatic PPGL patients suggest earlier detection of the disease compared to symptomatic cases. The lower metanephrine/normetanephrine ratio may indicate a higher prevalence of the norepinephrine-secreting phenotype in asymptomatic PPGLs. No pronounced differences were found in imaging characteristics between asymptomatic and symptomatic tumors.

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