Abstracts

Focal brain tumors are known to produce focal abnormalities on EEG. Rare reports exist in English literature about generalized epileptiform discharges in focal brain tumors., This is a series of three patients seen in our Epilepsy clinic, who were diagnosed with a brain tumor. The first patient was 25 year old man with history of complex partial seizures since age 10 years, who started having generalized tonic clonic seizures at age 23. MRI brain showed a lobulated circumscribed cystic lesion in left parietal lobe, likely a low-grade tumor. Video-EEG showed ictal and interictal runs of generalized frontally predominant 3Hz spike and wave discharges. The second patient was 4 year old boy with speech delay, who presented with complex partial seizures. Speech and behavior worsened over weeks, and video-EEG monitoring showed atypical absence seizures and epileptic spasms. EEG revealed frequent bilateral frontotemporal as well as abundant generalized spike and wave discharges. MRI brain revealed a mass involving the left inferior temporal lobe. A subtotal resection revealed Ganglioglioma grade 2. After surgery he is seizure free on Depakote. The third patient is a 4 year old boy with history of focal seizures since the age of 2 months. The initial EEG showed right frontotemporal spikes. At the age of 3 years, he started having drop attacks, with EEG showing abundant generalized frontally predominant polyspike and wave discharges. MRI revealed a tumor in the right medial temporal lobe. He underwent surgery at another institute., , Typical EEG features of tumor-associated epilepsy are: focal discharges, focal slowing or occasionally generalized slowing. Review of literature reveals that 30-92% of patients with epilepsy and brain tumors have regional slowing. Generalized abnormalities (e.g. slow activities) are seen mainly in focal brain tumors located in the midline or posterior fossa. Little information is available regarding EEG findings in hemispheric brain tumors in children. Generalized epileptiform discharges are mainly seen in generalized epilepsy syndromes and rarely in focal brain lesions. All 3 patients started with partial seizures and later on developed generalized seizures such as epileptic spasms, atypical absences, tonic seizures and drop attacks, confirmed by VEEG. EEG showed abundant generalized discharges besides focal abnormalities, which may probably be secondary to rapid bilateral synchrony. During infancy and early childhood, focal brain lesions may be accompanied by diffuse cortical excitability, evidenced by multifocal spikes. Generalized discharges have been reported in children with infantile spasms and brain tumors. Generalized epileptic discharges in presence of focal tumors may, in part, be explained by the same theory for infantile spasms with focal lesions proposed by Chugani et al. that the primary cortical generator interacting with subcortical structures to result in infantile spasms. How a focal primary brain tumor produces generalized or multifocal spikes is unknown.,