胃肠道外间质瘤CT及MRI表现与病理对照

CT/MRI FINDINGS AND PATHOLOGICAL MANIFESTATIONS OF EXTRAGASTROINTESTINAL STROMAL TUMOR

目的探讨胃肠道外间质瘤(EGIST)CT及MRI表现特点及其与病理对照。方法收集经病理及免疫组化检查确诊为腹部EGIST病人22例,对病灶CT及MRI平扫、增强扫描图像及病理特点进行分析。结果EGIST病人22例中,单纯CT检查13例,单纯MRI检查4例,同时进行CT及MRI检查5例。3例病人多发,其中2例多发病灶为腹腔种植转移(原发灶分别位于大网膜、腹膜后),1例为大网膜区及右侧附件区各1包块;19例病人单发,其中发生在大网膜4例,小网膜2例,肠系膜6例,腹膜后间隙6例,肝左叶1例;包块最大直径为2.9~19.4 cm(平均9.8 cm);病灶形态呈类圆形9例,分叶状13例。大体病理见肿瘤多数无真正包膜,切面主要为灰白色,光镜下由梭形细胞及上皮细胞构成。18例行CT检查病例中,密度不均15例,病变内见大小不一低密度区,病理上对应囊变、坏死区域;7例病变CT或MRI显示钙化,术后病理也可见钙化;CT增强扫描肿瘤实性成分动脉期呈轻度强化,静脉期多为中度强化,囊变、坏死区无明显强化。MRI扫描信号多不均,T 1WI为等低信号,T 2WI呈稍高信号,DWI表现为高信号,增强扫描肿瘤实性成分呈中度到明显不均匀强化。结论腹部EGIST的影像学表现具有一定特征性,CT及MRI检查可为EGIST临床诊断提供重要依据。

Objective To investigate the CT/MRI features and pathological manifestations of extragastrointestinal stromal tumor(EGIST).Methods A retrospective analysis was performed for the clinical data of 22 patients who were diagnosed with abdominal EGIST by pathology and immunocytochemistry,and the features of plain CT/MRI,contrast-enhanced CT/MRI scan,and pathological examination were analyzed.Results Among the 22 patients with EGIST,13 underwent CT alone,4 underwent MRI alone,and 5 underwent both CT and MRI.Of all patients,3 were found to have multiple masses,among whom 2 patients had the multiple lesions of abdominal implantation metastasis,with the primary tumors located in the greater omentum and the retroperitoneal space,and 1 patient had one mass in the greater omentum and one in the right adnexal area;the other 19 patients had single mass,among whom 4 had the mass in the greater omentum,2 had the mass in the lesser omentum,6 had the mass in the mesentery,6 had the mass in the retroperitoneal space,and 1 had the mass in the left lobe of the liver.The maximum diameter of the mass was 2.9-19.4 cm(mean 9.8 cm),and the shape of the masses was oval in 9 patients and lobular in 13 patients.Gross pathology showed that most tumors had no real capsule,with a grayish-white color of the section,and the tumors were composed of spindle cells and epithelial cells under a microscope.Among the 18 patients who underwent CT,15 had uneven densities,with different sizes of low-density areas within the lesions,which corresponded to the areas of cystic change and necrosis in pathology;7 had calcification in the lesions on CT or MRI,which corresponded to calcification in postoperative pathology.Contrast-enhanced CT scan of the solid components of tumors showed mild enhancement in the arterial phase,moderate enhancement in the venous phase,and no enhancement in the areas with cystic change and necrosis.Uneven signals were observed on MRI,with hypointensity on T1WI,slight hyperintensity on T2WI,and hyperintensity on DWI,and contrast-enhanced scan of the solid components of tumors showed moderate or significant heterogeneous enhancement.Conclusion Abdominal EGIST has characteristic imaging findings,with cystic change and necrosis in most cases.Contrast-enhanced CT/MRI scan mainly shows mild to moderate progressive enhancement.CT and MRI examinations can provide an important basis for the clinical diagnosis of EGIST.