Leiomyosarcoma of vascular origin is an extremely rare lesion especially when it occurs in the arteries. In the present study, we report a case of such a neoplasm, originating in the wall of the descending aorta and give an ample review of world references on the subjects of primary aortic neoplasm. Wright classified aortic tumors into two categories concerning the site of origin in the aortic wall: the first involves the intima, the second group consists of tumors arising in the media or adventitia. The aspecific clinical findings that characterize these lesions explain the difficulty of a preoperative diagnosis. Very important, therefore, are sonography and CT which point out signs and symptoms which refer to a local and distal diffusion of the tumor. However, even in the cases in which the diagnosis is done before surgery, there is no codified therapeutic management. In fact both surgical and non-surgical methods (radiotherapy, chemotherapy) have poor results with an average survival. Due to the limited prognosis "quoad vitam", the elective therapy must preferably be of conservative type.