A forty-eight-year-old Japanese woman with leiomyosarcoma of the infer
ior vena cava presenting as Budd-Chiari syndrome is reported. A large
tumor originating from the venous wall grew into the lumen, obstructin
g the hepatic vein, and extended up to the right atrium. Although this
is a very rare tumor, care should be taken in order to make an early
diagnosis and manage the condition effectively.