Leiomyosarcoma of the Innominate Vein: A Smooth Muscle Criminal.

Leiomyosarcomas of vascular origin are extremely rare malignant tumors that can present a diagnostic challenge when they present as a mediastinal mass. Although they portend a poor prognosis with both aggressive local symptoms and metastatic disease, we present a rare case in which surgical en bloc resection of the tumor was curative.