Alan Cohen, director of Johns Hopkins pediatric neurosurgery, shares the case of a 12-year-old boy who had a generalized seizure that led him to the emergency room. An MRI showed a tumor in the left parietal lobe of the brain. Using frameless stereotactic guidance and intraoperative MRI, Cohen and his team carefully removed the tumor, which had scalloped the overlying skull with pressure since it arose from the cerebral cortex. Pathology identified the tumor as a rare benign ganglioglioma, WHO grade 1.