Spontaneous thrombolysis of a large caval thrombus after insertion of an inferior vena cava filter: diagnosis and follow-up by ultrasound.

In the ultrasonic evaluation of a patient with a right-sided subphrenic abscess, coincidentally, a large inferior vena cava thrombus was found and subsequently proved by cavography. Considering the clinical condition of the patient, abdominal surgery was not performed, and instead a percutaneously inserted caval filter was successfully placed above the thrombus. The patient received oral anticoagulant therapy and after 6 weeks, ultrasound demonstrated complete thrombolysis.