RESUMEN
The authors, after having analyzed the clinical patterns and the causes producing cava syndrome, propose a sequential diagnostic approach to it, whose course makes use of radiological procedures more or less invasive, and of endoscopic and histobioptic techniques. Among radiological investigations pan-cavography has allowed the authors to formulate the diagnosis of limited venous return because of intrinsic causes, conferring so an aetiological connotation and a physiopathological correlation indispensable for a correct and rapid therapy of the uncommon "intrinsic cava syndrome" of two patients, suffering respectively from "idiopathic thrombosis of superior vena cava, concerning also the beginning of inferior vena cava" and from "Fiedler cardiomyopathy".