Liposarcoma of soft tissue: MRI findings with pathologic correlation

The MR images of seven liposarcomas were reviewed retrospectively to assess the tumor size, location, margination, signal characteristics and enhancement patterns in differnt histologic types. Seven liposarcomas comprising three well-differntiated, two myxoid and two pleomorphic types were evaluated. All tumors showed well-defined and mostly lobulated margins. The well-differentiated liposarcomas were composed mainly of fat with septations or nodules, were hyperintense on T2-weighted images, and demonstrated faint enhancement or no enhancement following intravenous constrast. Myxoid liposarcomas were homogeneous or mildly heterogenous and a pseudocapsule was present in one case. Pleomorphic tyes showed a markedly heterogeneous internal structure. Both myxoid and pleomorphic lesions-showed moderate or marked heterogeneous enhancement after contrast administration. Well-differentiated liposarcomas may by differntiated from other types of the tumor by their largely lipomatous apperance. The malignancy grade increases in parallel with tumor heterogeneity and contrast enhancement. (orig.)