Pararenal vena cava leiomyosarcoma versus leiomyomatosis: difficult diagnosis.

Inferior vena cava (IVC) leiomyosarcoma is a rare cancer treated with wide surgical resection. IVC leiomyomatosis is a benign tumor treated with open caval excision. A patient with an IVC tumor with iliocaval thrombosis was treated with thrombolysis and iliac stents. The patient was sent 1 year later to our institution with an IVC mass. Transvenous biopsy was consistent with leiomyomatosis. At surgery, the lesion was adherent, resected and the IVC reconstructed. Pathologic evaluation documented well-differentiated leiomyosarcoma not leiomyomatosis. Thorough evaluation of iliocaval thrombosis is recommended before endovascular management. Diagnostic modalities may be inadequate to differentiate leiomyosarcoma from leiomyomatosis.