Atretic Parietal Cephalocele With First Trimester Chiari Malformation and Sinus Pericranii Companion Case.

Encephaloceles are the type of dysraphism in which a skull defect allows for herniation of meninges, with or without the inclusion of neural tissue, and are commonly associated with agenesis of the corpus callosum. Encephaloceles are classified as frontal, occipital, or parietal, with parietal cephaloceles, or vertex cephaloceles (VC), being the least common. Despite this, VCs present as the most common cause of a midline scalp mass, displaying complex venous and neural malformations commonly referred to as the "tip of the iceberg." Atretic parietal encephaloceles (APC), a type of VC, are benign lesions arising from meningeal and vestigial tissue which have undergone fibrotic degeneration. As a result, prognosis will generally be better than other encephaloceles due to vestigial tissue involvement. Here, we report a neonate presenting with APC, corpus callosum agenesis, and a cingulate gyrus lesion, along with a sinus pericranii companion case for comparison.