胎儿先天性中胚叶肾瘤三例分析

Fetal congenital mesoblastic nephroma:analysis of three cases

目的分析胎儿先天性中胚叶肾瘤(congenital mesoblastic nephroma,CMN)的产前MRI和生后CT表现。方法2017年8月至2019年4月,3例单胎妊娠孕妇在广州市妇女儿童医疗中心产前影像检查疑诊胎儿CMN,新生儿在本院出生且生后经过外科手术切除和病理检查证实。回顾性分析3例胎儿的产前MRI、生后CT和病理检查资料,总结胎儿CMN产前MRI和生后CT的表现。对数据采用描述性统计分析。结果(1)本单位同期新生儿分娩总量为57716例,CMN发生率为0.005%(3/57716)。3例患儿均为男性,例1和例2孕期羊水过多,例3孕晚期突发胎儿窘迫、胎儿心包积液且肿物明显增大,均采取剖宫产分娩。(2)产前MRI检查,例1和例3病灶位于左肾,例2位于右肾。3例肿物均呈类圆形,边界清晰,T2加权稍高信号。例1和例2 T1加权等信号;例3 T1加权稍低信号,弥散加权高信号。(3)生后CT检查,例1和例2平扫呈均匀等密度,CT强化特点呈“包裹征”。例3生后CT平扫瘤体密度不均匀,瘤体内大片状高密度出血;CT强化呈结节状不均匀强化,并瘤内出血。(4)术后病理检查,例1和例2为经典型,例3为细胞型。结论经典型CMN的产前MRI特点是信号均匀,T1加权信号呈等信号,生后CT增强表现为“包裹征”;细胞型CMN的产前MRI特点是信号不均匀,T1加权信号减低,生后CT平扫表现密度不均匀,瘤内出血,增强呈结节状不均匀强化。但由于本研究病例数较少,需要积累更多病例,进一步研究。

Objective To analyze the characteristics of prenatal MRI and postnatal CT images of fetal congenital mesoblastic nephroma(CMN).Methods We retrospectively recruited three women with a singleton pregnancy suspected of having fetal CMN by prenatal imaging examination and confirmed by postpartum surgical resection and pathological examination at Guangzhou Women and Children Medical Center from August 2017 to April 2019.The prenatal MRI,postnatal CT,and pathological examination data were analyzed to summarize the image features of fetal CMN using descriptive statistical analysis.Results(1)The total number of deliveries in the setting during the same period was 57716,and the incidence of CMN was 0.005%(3/57716).All the cases were male and born through cesarean section due to polyhydramnios for case 1 and 2 and sudden fetal distress,fetal pericardial effusion with enlarged mass in the third trimester for case 3.(2)Prenatal MRI examination found that the lesions in case 1 and 3 were located in the left kidney,and in the right kidney in case 2.The tumors in the three cases were all around with clear borders and hyperintense signal on T2-weighed imaging(T2WI).Iso-signal on T1WI was noted for case 1 and 2,a slightly hypointense signal on T1-weighed imaging(T1WI),and a hyperintense signal on diffused weighed imaging were noted for case 3.(3)Postnatal CT plain scan showed uniform density tumor in cases 1 and 2 with"packing sign"in CT enhancement.Non-uniform density,internal,larger and high-density bleeding tumor was found in case 3,and the CT enhancement manifested as nodular,non-uniform,and intratumoral bleeding.(4)Postoperative pathological examination revealed that cases 1 and 2 were classic types,and case 3 was cellular type.Conclusions In this study,the prenatal MRI characteristic of CMN is a uniform signal,iso-signal on T1WI for classic type and non-uniform signal,and reduced signal on T1WI for cellular type.In classic type cases,postnatal CT enhancement showed a"packing sign."In contrast,in cellular type cases,the CT plain scan is manifested as non-uniform,intratumoral bleeding,and the enhancement pattern showed nodular and non-uniform enhancement.However,the results of this study is limited due to the small sample size and studies with larger sample size is needed in the future.