Malformation of the fetal brain in thanatophoric dysplasia: US and MRI findings.

We present a case in which the unusual cerebral malformations of thanatophoric dysplasia (TD) were identified on a 21-week fetal US and confirmed by antenatal MRI, postmortem imaging and autopsy. TD is the most common lethal skeletal dysplasia and is characterized by short long bones, which are often bowed (type 1), a small thorax, and skull deformities. There is also a recognised constellation of abnormalities of the brain primarily affecting the temporal lobes that, although well described in the postmortem setting, are not widely recognized in fetal imaging. Familiarity with this appearance will facilitate accurate antenatal diagnosis.