Soulié D, Boyer B, Lescop J, Pujol A, Le Friant G, Cordoliani Y S
Service de Radiologie, Hôpital d'Instruction des Armées du Val-de-Grâce, Paris.
J Radiol. 1995 Jan;76(1):29-36.
Myxoid liposarcoma is the most common type of liposarcoma (approximately 40 to 50% of all liposarcomas). The main tissue component is a myxoid matrix present primarily in extracellular compartments; proliferating lipoblasts account for less 10% of the tumor: MRI appearances are not typical for lipomatous tumor. Nevertheless histological features may permit understanding MRI findings and identifying patients with myxoid liposarcoma.
Clinical history and radiologic images of 7 patients with histologically verified myxoid liposarcoma were retrospectively studied. In all patients the tumor presented in a lower extremity as a painless, slowly growing mass. MR images were available for review in all cases (T1- and T2-weighted images); in addition fat-suppression before and after gadolinium enhancement were assessed with T1-weighted sequences.
MRI examination revealed an "encapsulated" tumor, non infiltrating and septated. On T1-weighted sequences all the lesions show lacy, amorphous and linear foci of high signal within a low signal of the tumor due to the predominance of a myxoid matrix. The high sensitivity of MRI demonstrates the presence of small areas of high signal and fat-suppression technique is valuable for characterizing soft-tissue tumors: suppression of high signal intensity on fat-saturated T1-weighted images indicates the presence of fatty tissue components.
Clinical correlation with MRI appearances on T1-weighted sequences (in addition to fat-suppression technique) may suggest the possibility of myxoid liposarcoma.
黏液样脂肪肉瘤是脂肪肉瘤最常见的类型（约占所有脂肪肉瘤的40%至50%）。主要组织成分是主要存在于细胞外间隙的黏液样基质；增殖的脂肪母细胞占肿瘤的比例不到10%；MRI表现对于脂肪瘤性肿瘤来说并不典型。然而，组织学特征可能有助于理解MRI表现并识别黏液样脂肪肉瘤患者。
回顾性研究7例经组织学证实为黏液样脂肪肉瘤患者的临床病史和放射影像。所有患者的肿瘤均出现在下肢，表现为无痛、生长缓慢的肿块。所有病例均有MR图像可供复查（T1加权和T2加权图像）；此外，还使用T1加权序列评估了钆增强前后的脂肪抑制情况。
MRI检查显示肿瘤为“包膜性”，无浸润且有分隔。在T1加权序列上，由于黏液样基质占优势，所有病变在肿瘤的低信号内均显示出花边状、无定形和线性高信号灶。MRI的高敏感性显示出小面积高信号的存在，脂肪抑制技术对于软组织肿瘤的特征性诊断很有价值：脂肪饱和T1加权图像上高信号强度的抑制表明存在脂肪组织成分。
临床与T1加权序列上的MRI表现（除脂肪抑制技术外）相关联，可能提示黏液样脂肪肉瘤的可能性。
