四肢软组织脂肪肉瘤MRI表现与组织分化的关系

Liposarcoma of the extremities: MRI appearanes:correlation with histologic differentiation

目的：探讨四肢软组织脂肪肉瘤MRI表现与组织分化程度的关系。方法：回顾性分析6例脂肪肉瘤MRI术前图像，与术后病理组织分化程度相对照评价MRI在肿瘤的大小、形态、边界、信号特点和邻近组织结构侵犯的情况，以找出它们间的关系。结果：6例脂肪肉瘤，其中分化良好型2例，粘液型3例，多形性1例，分化良好型脂肪肉瘤因含有较大量分化成熟的脂肪细胞，在T1和T2加权均免条索状高或较高信号，肿瘤边界清楚、信号较均匀，邻近组织结构不易受累。粘液型脂肪肉瘤含大量粘液基质，仅有少量分化良好、增生的脂肪母细胞，在MRIL无或仅有少量的脂肪信号，信号轻度不均匀。多形性脂肪肉瘤属高度恶性肿瘤，瘤内有大量的出血和坏死，信号明显不均匀，通常无明显脂肪信号显示，周围组织结构受浸润和水肿。结论：根据脂肪肉瘤的MRI表现，可评估肿瘤的分化和恶性程度。

To investigate the MRI findings of extrmity soft tissue liposarcoma and correlate them with the delve of histopathologic differentiation. Methods: Preoperative MRI findings and postoperative pathology of six liposarcomas were analysed retmspectively. 'l'he tumor size. morpholgy. margination. signal characteristic and relationship Of the tumor to adjacent structures were also assessed, and correlating them with surgical pathology. Results: Among 6 cases Of liPosarcoma there were 2 cases of well differentiated 3 myxoiltype, one pleomorphic. Well－differentiated liposarcoma contains a large amount Of well－differentiated lipocytes pathologically. showing linear high or relatively high signal Intensity (SI) on T1WI and T2ar, tumor is well defined homogeneous in SI, adjacent structures were not invased readily. My－cold－type liposarcoma is composed mainly of my－cold matrix containing a few well－(lifferentiated proliferating lipoblasts, demonstrating no or little signal on MRI characteristic for fal. mildly inhomogeneous. Plepmorpic－type liposarcoma is a high－grade malignant tumor, usualy containing areas of hemorrhage and necrosis. obviously hetergeneous. no signal characteristic for fat adjacent structures is infiltrated and edematous. Conclusion: The degree of histolog differentiation and malignancy can be evaluated on the basis of MRI findings of liposarcoma.