四肢黏液样脂肪肉瘤的MRI诊断

目的探讨四肢黏液样脂肪肉瘤的临床和MRI特点。方法对7例经病理证实的四肢黏液样脂肪肉瘤的临床和MRI资料进行了回顾性分析。患者年龄41-59岁，中位年龄51岁。结果3例肿瘤发生在大腿，2例在小腿，1例在足部，1例在肩部；6例位置深在，1例位置表浅。与肌肉相比病变在T1WI上主要呈等或稍低信号，6例可见“线”状、“花边”状或“云絮”状高信号；在T2WI上病变与脂肪相比大部分区域呈高信号；增强扫描病变均呈不均匀的显著强化；病变内部可见分隔，边缘清楚，周围无明显水肿，均未侵犯邻近骨骼。结论四肢黏液样脂肪肉瘤MRI表现有一定特点，在T1WI上主要呈等或稍低于肌肉的信号，并可见脂肪成分所致的“线”状、“花边”状或“云絮”状高信号，在T2WI上则以高于脂肪的信号为主，增强扫描呈不均匀的显著强化。

MRI diagnosis of myxoid liposarcoma of extremities

Objective To explore the clinical and MR imaging features of myxoid lipesarcoma. Methods Clinical and MR imaging data of 7 patients with histologically confirmed myxoid lipesarcomas on extremities were retrospectively analyzed. The age of the patients ranged from 41 to 59 years with a median age of 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 hypefintense 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 lipesarcomas is usually pronounced and heterogeneous.