Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Figure Caption
Atretic cephalocele is a true cephalocele that consists of dura, fibrous tissue, and dysplastic brain tissue. Classic MRI findings may include a well-defined calvarial defect (long arrow in B) with an adjacent round scalp lesion with a low T1 signal and a heterogeneous T2 signal (short arrows) at the midline parietal region. An upward-pointing primitive falcine vein replaces the straight sinus (asterisk). A CSF-like dorsal cyst beneath the falcine vein (hash sign) usually occurs in the alopecic type. Top differential diagnoses include dermoid/epidermoid cysts, which have high signal on T1-weighted and diffusion-weighted images. Sinus pericranii typically has scalp vascular enhancement and developmental venous anomalies.