MRI diagnosis of myxoid liposarcoma of extremities

Objective: To explore the clinical and MR imaging features of myxoid liposarcoma. Methods: Clinical and MR imaging data of 7 patients with histologically confirmed myxoid liposarcomas on extremities were retrospectively analyzed. The age of the patients ranged from 41 to 59 years with a median age or 51 years. Results: Three tumors occurred in thigh, two in calf, one in foot and one in shoulder. Six tumors were situated deeply, and one was superficial. On T₁-weighted images, all 7 tumors showed predominant isointense or slightly hypointense signals relative to muscle, with 6 having lacy, linear or amorphous foci of high signal intensity. The major portion of each tumor displayed hyperintense signals compared with fat on T₂-weighted images. Following the injection of Gd-DTPA, all tumors showed inhomogenous and strong enhancement. All tumors had septa and were well defined without obvious surrounding edema and invasion of the adjacent bones. Conclusion: Myxoid liposarcomas usually show predominant isointense or slightly hypointense signals relative to muscle on T₁-weighted images and hyperintense signals relative to fat on T₂-weighted images. The fat components within the tumors may be identified as linear, lacy or amorphous foci of high signal intensity on T₁-weighted images. The contrast enhancement of the myxoid liposarcomas is usually pronounced and heterogeneous. (authors)