Classic Case

Figure Caption
Atretic cephalocele is a true cephalocele that consists of dura, fibrous tissue, and dysplastic brain tissue. The classic imaging features may include a well-defined calvarial defect (long arrow in A) with an adjacent round scalp lesion with low T1 signal (short arrow in A), heterogeneous T2 signal (arrow in B), and no enhancement at the median parietal convexity. An upward-pointing primitive falcine vein replaces the straight sinus (asterisk). Top differentials include dermoid/epidermoid cysts, which typically have high signal on T1- and diffusion-weighted images. Sinus pericranii typically has vascular enhancement. More aggressive lesions such as metastases usually have accompanying destruction of the surrounding calvarium.