纵隔少见恶性肿瘤的CT及PET/CT诊断

CT and PET/CT in the Diagnosis of Rare Malignant Mediastinal Tumor

目的探讨纵膈少见恶性肿瘤的CT及PET/CT表现,提高术前诊断率。方法回顾性分析经病理证实的纵膈少见恶性肿瘤28例,28例均行CT平扫及增强扫描,其中5例一周内行18-FDG-PET/CT检查。结果 28例中,男24例,女4例,平均年龄42岁。包括胸腺癌9例,上皮来源性恶性肿瘤9例,生殖源性肿瘤7例,恶性孤立性纤维瘤、恶性节细胞嗜铬细胞瘤及硬化性脂肪肉瘤各1例。CT平扫为单发巨大等低密度软组织影,平均大小为8.3cm,3例病灶内见脂肪影,4例病灶中央伴斑点状钙化;3例呈圆形或卵圆形,25例呈分叶状;25例边缘不清,3例边缘尚清晰;增强呈中度或明显强化,8例伴坏死无强化区。5例纵膈及肺门淋巴结转移,2例胸膜转移,8例胸腔积液,1例胸椎骨转移。PET的SUV值平均12.4(范围4.7-17.8)。结论纵膈少见恶性肿瘤多具有恶性肿瘤的共同特征,CT表现多无特征性,但CT检查能清晰显示肿瘤大小、密度、边缘及对周围组织的侵犯,SUV值呈高摄取,CT与PET/CT相互结合有助于提高诊断率。

Objective To investigate CT and PET-CT features of rare malignant mediastinal tumor and improve the preoperative diagnosis rate.Methods 28 cases with rare malignant mediastinal tumor confirmed pathologically were retrospectively analyzed.Plain CT scanning and contrast enhancement were performed to all cases,and 18-FDG-PET/CT was performed to 5 cases within a week among them.Results Among all 28 cases,24 cases were male and 4 cases were female.The average age of patients was 42 years old.All cases were categorized into 6 different tissue sources including thymic carcinoma（n=9）,malignant tumors originating from epithelial cells（n=9）,tumors originating from germ cells（n=7）,malignant solitary fibroma（n=1）,malignant pheochromocytoma of Ganglion cells（n=1）,sclerosing liposarcoma（n=1）.Plain CT scanning showed the single,large and isodense or hypodense mass.The average size was 8.3 cm.Fat density areas were found in 3 cases and stippled calcifications could be seen in 4cases.The masses were round or oval in 3 cases and lobulated in 25 cases.25 cases showed ill-defined edges,and 3 cases showed fairly well-defined edges.All cases showed moderate or obvious enhancement,and 8 cases also showed zones of necrosis which were not enhanced.5 cases showed mediastinal and hilar lymph node metastasis,and 2 cases showed pleural metastasis.Hydrothorax was showed in 8 cases,and thoracic bone metastasis was showed in 1 case.The average SUV value was 12.4（ranges were 4.7-17.8）.Conclusion Rare malignant mediastinal tumors have common features with malignant tumors.CT features of rare malignant mediastinal tumors are not specific,but CT examination can show the size,density,edge and invision to surrounding tissues.The SUV value was highly intaked.It helps to improve the diagnostic rate by combining CT with PET/CT.