“…Typical symptoms of PHEO and PGL including the noticeable triad of palpitations, headaches, and sweating, nevertheless, cases of asymptomatic PHEO and PGL are increasing owing to the prevalence of physical examination, family and germline mutation testing (1,2). Unlike cases of PHEO with inferior vena cava (IVC) tumor thrombus that had been sporadically reported (3)(4)(5), PGL with IVC tumor thrombus is even rarer and only two cases Case Report Functional paraganglioma with tumor thrombus in the inferior vena cava, first case report had been publicly reported before, both of them were subclinical, asymptomatic, and accidentally discovered (6,7), report of PGL with the neuroendocrine function that invades the IVC is lacking. We present the following article in accordance with the CARE reporting checklist (available at http://dx.doi.org/10.21037/tau-21-50).…”