Self-Amputation of the Extra Digit in a Fetus with Polydactyly: First Ultrasound Demonstration.

We herein report the first ultrasound evidence of the self-amputation of an extra digit in case of fetal polydactyly. The prenatal evidence of fetal polydactyly is not always followed by postnatal confirmation. This is not always due to ultrasound misdiagnosis, but often to an in utero self-amputation phenomenon. We demonstrate that there is the detachment of part of the digit, leading to the evidence of a neonatal bump on the site of the prenatal extra digit. This demonstration has been possible by the direct visualization of the remnant by ultrasound.