Rasmussen Encephalitis

"Rasmussen encephalitis is a rare childhood syndrome characterized by medically refractory focal seizures and progressive multifocal neurologic symptoms such as hemiplegia and cognitive impairment . Pathologic analysis demonstrates chronic progressive unilateral inflammation of the brain of uncertain cause that results in progressive cortical atrophy . At present, early functional or anatomic hemispherectomy is the recommended treatment for seizure control, thereby preventing further cognitive impairment or the spread of inflammation to the contralateral cortex."  -  http://radiographics.rsna.org/content/28/4/1079.full#sec-7 

 Axial T2-weighted MR image shows atrophy of the right temporal lobe and insular cortex that had progressed over time (arrow).