探讨腹膜后内寄生胎产前和新生儿期的临床及超声影像特征。

收集湖北省妇幼保健院2016年1月至2020年1月产前超声检查发现宿主胎儿腹腔内肿块、于新生儿期手术并经病理证实为腹膜后内寄生胎8例。总结产前和新生儿期的临床资料及超声影像资料，并将超声特征与手术、病理结果进行对照分析。

8例腹膜后内寄生胎的超声影像特征为：囊实性肿块；肿块边界清楚，囊壁薄；实质性成分（寄生胎）随孕龄增长而增大，并渐具胎儿雏形，超声易识别发育不良的脊柱轴、颅骨环、长骨、肢芽、增厚的皮肤等结构，实质性成分周围包绕囊液；寄生胎有血管蒂与宿主血管分支相连；肿块多数位于腹腔中轴线稍偏左或偏右、脊柱和腹主动脉前方、双肾之间。临床结局为：8例均于出生后5~27 d手术，其中1例合并回肠美克尔憩室，1例合并成熟囊性畸胎瘤；其中4例行开腹手术，1例腹腔镜转开腹手术，3例行腹腔镜手术。8例术后均恢复良好，随访至今均未复发。病理结果为：8例腹膜后内寄生胎中单寄生胎6例，双寄生胎2例，共10个寄生胎。与病理结果对照，超声检出率最高的是骨性组织（9/9）、颅骨环（2/2）；其次是长骨（6/7）、脊柱轴（6/8）、肢芽（6/9）、血管蒂（6/10）和皮肤（4/10）。

腹膜后内寄生胎超声影像有特征性表现，并与临床手术及病理表现相对应。系统规范的超声检查可尽早正确诊断内寄生胎，对于宿主胎儿出生后选择合适的诊疗方法和治疗时机具有十分重要的意义。

To summarize the clinical and ultrasonographic features of retroperitoneal fetus in fetu (FIF) in the prenatal and neonatal period.

Eight cases of retroperitoneal FIF confirmed by pathology from January 2016 to January 2020 at Maternal and Child Health Hospital of Hubei Province were enrolled in this retrospective study. The clinical and ultrasonographic features of retroperitoneal FIF were analyzed and compared with surgical and pathological results.

The eight cases of retroperitoneal FIF were characterized by heterogeneous cystic-solid masses with clear boundaries and thin walls. FIF was typically enclosed within a distinct sac containing either fluid or sebaceous material, ultrasound can identify dysplastic spinal axis, skull ring, long bone, limb bud, thickened skin, and other structures, and the solid components were surrounded by cystic fluid. An umbilical cord-like structure served as the connection between the parasitus and the host. Most of the masses were located slightly to the left or right of the axis of the abdominal cavity. All the eight cases were operated on 5-27 days after birth, including 1 case with ileal Meckel's diverticulum and 1 case with mature cystic teratoma. Four cases underwent laparotomy, one underwent laparoscopic conversion to laparotomy, and three underwent laparoscopic surgery. All the eight cases recovered well after operation, and no recurrence was observed during follow-up. The coincidence rates of ultrasound with pathology were 9/9 for bone tissue, 2/2 for cranium ring, 6/7 for axial skeleton, 6/8 for vertebral column, 6/9 for limb buds, 6/10 for vessels, and 4/10 for skin.

The ultrasonic manifestations of FIF are characteristic and correlated with the clinical and pathological findings. Systematic and standardized ultrasound examination in the prenatal period can diagnose FIF as early as possible, which is of great significance for the selection of appropriate treatment methods and timing after birth.