Vascular soft tissue tumors: medical imaging.

Histologically, tumors of the vascular system are divided into three categories. Benign types can be localized (hemangioma) or involve large segments of the body (angiomatosis). Vascular tumors of intermediate malignancy are known as hemangioendotheliomas. Angiosarcoma is one of the rarest malignant soft tissue neoplasms. The authors present the morphological and SI features of 17 histologically proven vascular tumors (16 benign, 1 malignant) examined by MRI. The results are compared with the findings on other imaging techniques. On T1-WI, the tumors are slightly hyperintense to muscle with interspersed areas of low SI corresponding to fibrous septa, calcifications, or fastly flowing blood, and areas of SI equal to fat. On T2-WI, the lesions are more homogeneous and markedly hyperintense to fat. MRI is superior to all other imaging techniques for evaluation of extent and characterization of vascular soft tissue tumors. Angiography remains helpful in demonstrating feeding or draining vessels.