四肢、躯干软组织原发性脂肪肉瘤的CT和MRI诊断

CT and MRI diagnosis of primary liposarcoma of extremities and trunk

目的:探讨四肢、躯干软组织原发性脂肪肉瘤CT和MRI特点,以提高其诊断水平。方法:对经手术及病理证实的12例四肢、躯干软组织原发性脂肪肉瘤的CT和MRI表现及特征与术后病理标本进行回顾性对照分析。其中行CT检查7例,MRI检查11例,二者均检查6例。结果:12例中,分化成熟型6例,黏液型3例,多形性2例,去分化型1例。肿瘤形态不规则7例,规则5例,直径6.1～19.9cm。分化成熟型含有大量成熟脂肪,CT和MRI显示脂肪组织,密度/信号较均匀,边界清晰;黏液样脂肪肉瘤含有丰富黏液基质,部分含有分化较好的脂肪团,CT和MRI显示脂肪团,密度/信号较不均匀;多形性脂肪肉瘤密度/信号不均匀,邻近组织易累及和瘤周水肿;去分化型瘤体体积大,密度/信号明显不均匀,增强明显强化。结论:CT和MRI表现及特征能反映四肢、躯干软组织脂肪肉瘤的组织学特点,可清楚地显示肿瘤的大小、边界、累及范围及其与周围组织的关系,可初步评估肿瘤的分化及恶性程度。

Objective：To analyze the CT and MRI features of liposarcoma of the extremities and trunk for improving the diagnosis of the disease. Methods：The CT and MRI findings of 12 cases of primary liposarcoma confirmed by operation and pathology were analyzed retrospectively. Seven cases were examined by CT, 11 cases by MRI ,and 6 cases by both CT and MRI. Results：Among the 12 cases, 6 were well differentiated liposarcoma, 2 selerosing liposarcoma, 3 myxoid iposarcoma, 2 pleomorphic and 1 was dedifferentiated liposarcoma. Seven cases were irregnlarly margined and five cases regnlarly margined. The mean diameter of the lesions ranged from 6.1 to 19.9 cm. Well differentiated liposarcom contained a large amount of mature fat. CT and MRI showed fat tissue which was well defined, and homogeneous in density and signal intensity（SI）. Myxoid liposarcoma consisted mainly of myxoid matrix, containing a few well differentiated proliferating lipoblasts;CT and MRI demonstrated no or little fat with irregular density and mildly inhomogeneous SI. Pleomorphic liposarcoma had no characteristic of fat tissue, and the adjacent structures were infiltrated and edematous with apparently inhomogeneous density and SI. Dedifferentiated liposarcoma had a pretty large volume with apparently inhomogeneous density and SI. The enhancement was highly intensified. Conclusions： CT and MRI can reflect the histological features of liposarcoma of the extremities and trunk, and demonstrate the exact boundaries of tumors, the actual area and surrounding tissues. The degree of histology differentiation and malignancy can be evaluated on the basis of CT and MRI findings of liposarcoma.