腹膜后炎性肌纤维母细胞瘤的CT特征

CT characters of retroperitoneal inflammatory myofibroblastic tumor

目的：探讨腹膜后炎性肌纤维母细胞瘤（IMT）的CT特征。方法回顾性分析11例经病理证实的腹膜后IMT患者资料，均行腹部CT平扫及双期增强扫描，观察其CT表现。结果11例腹膜后IMT中，椭圆形1例、不规则团块状4例、分叶状6例；位于肾周区4例、腹主动脉旁2例、胰胃间2例、盆部髂血管旁3例；肿瘤最大径5.9～16.7 cm，中位最大径平均6.1 cm。CT平扫10例呈低密度，1例等密度。增强扫描动脉期9例呈中等及以上程度强化，2例呈轻、中度强化；静脉期11例均持续强化。病灶强化方式多样，其中3例呈不均质强化实性肿块；6例呈结节、片絮状及岛状强化实性区伴程度不等的黏液变性区；2例肿瘤黏液变性为主，周边及黏液区混杂结节、岛状及条片状强化实性区。2例病灶边界清楚，9例边缘较毛糙，可见范围不等的小片状或“晕环”状渗出模糊影。5例伴有邻近腹膜增厚及腹腔少许积液，2例侵及脾脏，4例侵犯腰大肌，3例包绕输尿管继发同侧肾积水，6例包绕邻近大血管。结论腹膜后IMT除具有肿瘤较大、形态多不规则、边缘模糊并见小片状或“晕环”渗出等共性特征外，不同病理类型的病灶CT动态增强表现具有多样性。CT对其诊断具有一定价值。

Objective To explore the CT characters and corresponding pathological bases of retroperitoneal inflammatory myofibroblastic tumor（IMT）. Methods The CT and clinical data of 11 cases of retroperitoneal inflammatory myofibroblastic tumor proved by pathological results were analyzed retrospectively. Results Among 11 cases, 4 cases showed irregular mass, 6 lesions showed lobular configuration and 1 lesion was oval. Four lesions were located in the fatty clearance of kidney, 2 in the clearance of pancreas and stomach, 2 near the celiac aorta and 3 near the iliac vessels. The range of maximum diameter was 5.9 to 16.7 cm and the mean was 6.1 cm. On unenhanced CT, 10 tumors showed low density and 1 showed equal density. On arterial phase of the enhanced CT of 9 tumors showed moderate or vivid enhancement and 2 tumors showed mild to moderate enhancement, and on the vein phase of enhanced CT, all 11 tumors showed persistent obvious enhancement. The enhanced pattern was various： 3 cases showed solid mass with inhomogeneous enhancement, 6 cases showed solid-cystic mass with nodular, patch enhancement and some mucious degeneration, 2 tumors showed remarkable mucious degeneration with peripheral foci of enhancement. The local boundary of 9 tumors were dim and with exudation presenting as“small slice”or“halo”. Five tumors were accompanied with the thickening of adjacent peritoneum and ascites, 2 tumors infringed spleen, 4 cases infringed psoas major, 3 cases encircled the ureter of the same side and resulted in uronephrosis, 6 cases encircled adjacent blood vessels, while the boundary of the rest 2 tumors were clear relatively. Conclusions Retroperitoneal inflammatory myofibroblastic tumors show certain common characters such as huge mass with irregular shape and dim edge together with exudation of“small slice”or“halo”. The dynamic enhanced CT of different pathological types can show certain individual characters, which may be of value in the diagnosis of retroperitoneal inflammatory myofibroblastic tumor.