Adipose tumors of soft tissues.

Thirteen patients with lipoma were examined at least with MRI, which revealed homogeneous and high signal lesions in both T1 and T2 WI sequences. On CT, these lesions were characterized by very negative density values. Sonography was useful to differentiate a lipoma from an old hematoma that share the same signal on MRI. Eighteen cases of biopsy proven liposarcomas were evaluated with at least two techniques. Tumor heterogeneity was the most important clue to malignancy. With CT, contrast injection was necessary because two cases out of eight appeared homogeneous on native examinations. Lobular pattern and large size are constant signs associated with liposarcoma. The correlation of imaging and histology classification was only successful with differentiated tumors. Angiography unspecifically reveals the malignancy of liposarcoma. MRI is better than CT to evaluate tumor expansion and to differentiate the mass from the surrounding tissue.