原发性肾肉瘤的影像表现

Imaging findings of primary sarcoma in the kidney

目的探讨肾脏原发性肉瘤的影像特点。方法回顾性分析有影像检查经手术病理证实的７例原发性肾肉瘤，包括平滑肌肉瘤３例，脂肪肉瘤、纤维肉瘤、恶性纤维组织细胞瘤及恶性神经鞘瘤各１例。ＣＴ检查６例，超声检查６例，ＭＲＩ检查１例。结果肿瘤发生在肾实质６例，肾盂１例。肿瘤形态为不规则块状５例，球形２例。边缘模糊６例，与肾实质分界不锐利。ＣＴ显示４／６例肾实质病变密度不均匀，内有坏死区，其中２例增强扫描有中或高度强化，２例平扫密度均匀。声像图中４／６例呈中等不均质混合回声，恶性纤维组织细胞瘤及脂肪肉瘤呈低回声且均匀。ＭＲＩＴ１ＷＩ相肿瘤为近等信号团块；Ｔ２ＷＩ相肿瘤为中等不均质高信号；Ｔ１ＷＩ增强后肿瘤有强化，且低于肾实质，内信号更加不均匀。纤维肉瘤伴有下腔静脉及肾静脉内大瘤栓。结论肾脏原发性肉瘤具有典型的恶性肿瘤影像表现，而无组织学特异征象，与肾癌无法区别。ＣＴ增强扫描及ＭＲＩ检查有助于显示肿瘤部位、范围、密度／信号改变。

Objective To reveal the characteristic findings of primary sarcoma of the kidney. Methods From December 1988 through February 1996, seven cases of renal sarcoma confirmed by histo pathology were retrospectively reviewed,including 3 leiomyosarcoma and 1 for each of liposarcoma,fibrosarcoma, malignant fibrous histiocytoma and malignant Schwannoma. Image material: CT in 6 cases, ultrasonography in 6 cases and MRI in 1 case. Results The tumor was located in renal parenchyma in 6 cases and in renal pelvis in 1 case. On the images,it was commonly a large mass with irregular margin, indefinite,circumscribed and heterogeneous in density with necrosis inside as observed on the CT scan and 2 cases with median to hyperattenuation on the enhanced CT scan; 4/6 cases gave median heterogeneous mixed echo and 2/6 cases appeared as even hypoechoic mass on the ultrasonogram. On MRI,the mass gave isosignal intensity on T 1WI and increased signal intensity with moderete heterogeneity was seen on T 2WI or became more enhanced and heterogeneous but no more than renal parenchyma on the enhanced T 1WI of MRI. Big tumor thrombus in the inferior vena cava and renal vein was noted in the fibrosarcoma. Conclusions Primary renal sarcomas give imaging findings characteristic of malignant tumor but without histological specificity and can not be differentiated from renal cell carcinoma. The enhanced CT and MRI capable of providing useful information of the localization, changes in density /signal and extent of invasion of the tumor,are beneficial to the differential diagnosis and managements.