Purpose or Case Report: Atretic cephalocele is a rare type of neural tube defect that occurs in the parietal or occipital scalp. Most cases present postnatally with a scalp nodule which may also have associated skin and hair abnormalities. We will present a case of atretic cephalocele diagnosed with fetal MRI as well as two additional cases of postnatally diagnosed atretic cephalocele in different patients.

A 26 week gestational age male fetus was found to have ventriculomegaly on routine OB ultrasound and was referred to maternal fetal medicine. Further ultrasound imaging demonstrated features suspicious for a posterior fossa encephalocele. A fetal MRI was then performed which demonstrated imaging findings consistent with an atretic cephalocele.

The imaging findings associated with atretic cephalocele including embryologic positioning of the straight sinus, the “spinning top” appearance of the tentorial incisura, and the “cigar shaped” CSF tract in the interhemispheric fissure will be illustrated in the exhibit using both fetal and postnatal MRI. Although the exact embryological development of atretic cephaloceles is not completely understood, the proposed mechanisms will be discussed. A brief summary of the associated syndromes and clinical outcomes reported in the literature will be presented.

Atretic cephalocele is a rare condition that is usually diagnosed postnatally with several characteristic imaging findings. These same abnormalities can also be seen on fetal MRI which can lead to an earlier diagnosis and more appropriate family counseling.
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