[Difficulties in distinguishing abnormal intensities associated with convulsion from tumor on MRI: a case report]

A 48-year-old man was admitted to our department with generalized convulsive seizures followed by recurrent partial clonic convulsions in the left face and arm. Convulsions stopped temporarily after administration of diazepam, fosphenytoin, and levetiracetam. However, frequent partial seizures occurred repeatedly and general anesthesia was required to control seizures. Diffusion-weighted and T₂-weighted images revealed a high-intensity lesion in the right frontal lobe. A tumor-like area in the white matter showed high intensity on T₂-weighted images with ring enhancement on gadolinium-enhanced T₁-weighted images. An area of frontal cortex near the tumor was also enhanced. Brain surgery was performed for the purposes of diagnosis, seizure control and tumor resection. Histological findings demonstrated oligodendroglioma in the ring-enhancing area, but not in the frontal cortex. This fact indicated that contrast enhancement of the frontal cortex was caused by status epilepticus. It is important to recognize that status epilepticus could cause contrast enhancement on magnetic resonance imaging.