Radiological findings of retroperitoneal leiomyoma and leiomyosarcoma: report of two cases.

Radiologic findings in cases of retroperitoneal leiomyosarcoma and leiomyoma were reported. These cases showed very similar findings: irregularly marginated large masses with central cyst formation and no calcification on CT and ultrasonography. Angiography showed tumor vessels and tumor stains. Cystic region due to central necrosis or hemorrhage was the most prominent radiologic finding in these cases. However, it was difficult to distinguish leiomyosarcoma from leiomyoma on the basis of the radiologic findings alone.