促纤维组织增生性小圆细胞肿瘤^18F-FDG PET-CT影像学表现及文献复习

目的探讨促纤维组织增生性小圆细胞肿瘤（DSRCT）的正电子发射体层摄影术（PET）-CT影像表现、诊断、鉴别诊断。方法经病理组织证实的2例DSRCT患者,男性,年龄均为27岁。回顾性分析其PET-CT影像学特点,并文献复习。结果PET影像表现为广泛腹、盆腔内不均质性葡萄糖代谢异常活跃灶,肿块内坏死区葡萄糖代谢呈缺失表现。CT表现为腹、盆腔内分叶状结节或团块状肿块,广泛侵及腹膜、网膜、浆膜面;内可见坏死区,伴点状钙化;增强CT呈轻中度不均质性强化,病灶对周围组织、器官呈推挤、包绕、侵犯倾向,边界不清,但与周围器官无明显起源关系。MRI显示：T1加权像病灶呈不均质性等、低信号,T2加权像病灶呈不均质性等、稍高信号,坏死区呈高信号,增强扫描呈不均质性轻中度强化。结论DSRCT罕见,临床表现复杂,病灶与浆膜关系密切,但也可发生在其他部位;PET-CT可以同机融合结构及功能显像行全身扫描,对DSRCT的诊断、分期、定位活组织检查及疗效评价有很高价值。

18F-FDG PET-CT image features of desmoplastic small round cell tumor and review of literature

Objective To study the PET-CT imaging characteristics, diagnosis and differential diagnosis of desmoplastic small round cell tumor（DSRCT）. Methods Two cases with pathologically confirmed of DSRCT patients, males, aged 27-year-old, were underwent PET-CT scan. The PET-CT and MRI imaging features were analyzed retrospectively, and relevant literatures were reviewed. Results The PET images demonstrated heterogeneously increased fiuorodeoxyglucose （FDG） uptake, necrosis showed lack of glucose metabolism, multiple peritoneal and mesenteric masses with an extensive seed. The performance of CT showed large, lobulated or nodular masses with heterogeneous hypodense in the abdominopelvic spaces. Peritoneal lesions were most commonly. Intratumoral necrosis and punctate calcifications could be found. On contrast enhanced CT scan, all lesions appeared mild to moderate heterogeneous enhancement, The mass trended to push, encase and invade surrounding tissues and vessels without any obvious organ origin. MRI showed hypointensity signal on T1 and slightly hyperintensity signal on T2. Cystic and necrotic zone appeared obvious hyperintensity signal on T2,showed mild to moderate heterogeneous enhancement with gadolinium. Conclusion It is demonstrated that DSRCT is a very rare peritoneal aggressive neoplasm, with high metastasis and poor prognosis. PET-CT could integrate with structural, functional imaging and whole-body scan. The PET-CT examination has high clinical value for the DSRCT.