EP17.39: Prenatal ultrasonic characteristics and pathological analysis of fetus in fetu

Abstract

To explore the prenatal ultrasonic characteristics of fetus in fetu. 8 cases of fetus in fetu that confirmed by pathology in our hospital were retrospectively analysed. There were 8 cases of fetus in fetu in this retrospective study. 4 cases were located in the retroperitoneum, 2 cases in the sacrococcygeal region, 2 case in the face. In these patients, the initial ultrasound diagnosis was made at different times of the gestation from 18+2 to 38+1 weeks. The cystic-solid masses found by ultrasound ranged from the minimum mass of 1.1cm × 1.1cm to the maximum mass of 16cm × 10cm. The ultrasonic imaging showed heterogeneous cystic-solid masses and the boundaries were clear. The surrounding organs were compressed as a result of the mass effect. 4 cases were diagnosed as fetus in fetu by prenatal ultrasound; 2 cases were thought to be teratomas; 2 cases were unclear. 4 cases in retroperitoneum were recovered by surgery after birth and no recurrence was found till now; the other 4 cases were done induced labour. Different organs were found in FIFs, including vertebral column, long bones, limb buds, skin and the vessels. Pathology comfirmed that the most common components were bone/cartilage and lumb bud (90%). Corroborated with pathology, the prenatal ultrasound coincidence rates were 100% of bone/cartilage, 85.7% of vertebral column, 83.3% of axial skeleton, and 71.4% of skin and vessels. Prenatal ultrasound did not detect some organs including hairs in 6 cases, intestinal tracts in 5 cases, kidney in 1 case and combined malformations including umbilical bulge in 2 cases, anencephalus in 2 cases, spina bifida in 1 case. The ultrasonic imaging of FIF is characteristic and the systemic prenatal ultrasound has a very important role in diagnosis of FIF.