Prenatal and postnatal imaging for early detection of sirenomelia: A case study.

Sirenomelia is a rare congenital caudal abnormality. We applied two-dimensional, three-dimensional, and color Doppler ultrasound to diagnose a fetus with sirenomelia at 12 + 6 weeks. The fetus exhibited on ultrasound fused lower limbs, two tibiae in lower legs, no fibulae, knees in retroflexion, pelvic hypoplasia, hypoplasia of the lower lumbar vertebrae and coccyx, bilateral renal agenesis, no bladder, and a single umbilical artery. The postnatal X-ray revealed a fetus with two femurs, two tibiae, and no fibula. The results of chorionic villus aspiration indicated that the fetus was male with a normal karyotype (46, XY), and the microarray results were normal.