良恶性胃肠道间质瘤的CT与病理对照研究

目的通过分析胃肠道间质瘤(GIST)的CT表现与其术后病理诊断结果,以提高CT对GIST的良恶性诊断水平。方法回顾分析25例经手术病理证实为GIST病人的CT检查资料,对比其术后良恶性的病理结果,找出其CT的良恶性征象,指导临床治疗。结果6例良性GIST的CT表现为类圆形肿瘤,边界清楚,5例直径小于5cm,5例强化值大于25HU,瘤灶内无出血、坏死,无周围结构侵犯;12例恶性GIST的CT表现为类圆形或分叶状肿瘤,10例直径大于5cm,9例强化值大于25HU,7例瘤灶内有出血坏死,9例周围侵犯或转移。7例潜在恶性GIST的CT表现介于两者之间。良恶性GIST的大小、平扫密度是否均匀、周围有无侵犯或转移及有无出血或坏死有显著差异(P<0.01)良恶性GIST的强化程度、免疫组化阳性率、细胞类型无显著差异。结论GIST缺乏临床、镜下病理及CT特征,需行免疫组化鉴别,但CT能充分显示病变部位及周围脏器侵犯情况,对GIST的良恶性鉴别诊断及术后随访有重要价值。

Benign and malignant gastrointestinal stromal tumors: CT findings and pathology

Objective Through a study of CT findings and the corresponding pathology of gastrointestinal stromal tumors (GIST), to improve the differential diagnosis of benign and malignant GIST. Methods CT was performed in 25 patients with GIST confirmed by pathohistology and the images were analyzed retrospectively. CT images were compared with the corresponding pathological results, in which the benign and the malignant CT features were concluded. Results In 6 cases of benign GIST, all lesions were oval-shaped and well-defined. 5 cases out of 6 were smaller than 5cm in diameter. The CT value increased over 25HU during contrast-enhancement in 5 cases. And there was no central hemorrhage and necrosis or involvement of adjacent organs. In 12 cases of malignant GIST, all tumors were oval-shaped or lobulated. 10 cases out of 12 were larger than 5 cm in diameter. CT value was elevated over 25HU in 9 cases during contrast-enhancement. Central hemorrhage and necrosis were found in 7 cases. The involvement of adjacent organs or metastasis was revealed in 9 cases. 7 cases of low grade malignant GIST shared various CT findings with the malignant or benign GIST. The size, non-enhanced density, adjacent involvement, distal metastasis, central hemorrhage and necrosis between malignant tumor and benign tumor were statistically different (p< 0.01), while no statistical difference was found in increased CT value during contrast-enhancement, positive rate of immunohistochemistry, or cell type. Conclusion GIST is lack of clinical, pathological, and CT imaging characterizes, and final diagnosis should be made with immunohistochemistry. But CT reveals the details of GIST and involvement of adjacent organs, which plays an important role in differential diagnosis of benign or malignant GIST and post-operative follow-up.