Focal brain herniation into giant arachnoid granulation: A rare occurrence

Arachnoid granulations are normal anatomical structure that allows cerebrospinal fluid (CSF) drainage from subarachnoid space into venous system. They are asymptomatic but rarely can become symptomatic when they are large enough to cause sinus occlusion. We report a rare occurrence of focal brain herniation into a giant arachnoid granulation in a pediatric patient after sustaining severe head trauma. We also highlight on the use of diffusion tensor tractography in helping to confirm the diagnosis.