Bilateral Rasmussen's encephalitis associated with type II focal cortical dysplasia: Dormant 'second' epileptogenic zone in contralateral disease.

Rasmussen's encephalitis (RE) is an inflammatory, probably autoimmune disorder manifested by refractory seizures and progressive deterioration of one cerebral hemisphere [1]. Here, we describe the unfortunate history of a girl with a progressive disorder which, upon clinical, neuroimaging, and histopathological evaluation, proved to be bilateral RE associated with type II focal cortical dysplasia. Whether the second pathology is relevant for the extent of the disease is discussed. We demonstrated histopathological evidence of RE and type II FCD in the left hemisphere, which led to EPC on the right hemibody at presentation. In addition, there was unequivocal progressive cortical and subcortical atrophy of the right hemisphere, which accounted for the EPC on the left hemibody. This is highly compatible with RE (+/- FCD) in the right hemisphere as well. Although the association of FCD and RE - as well as the occasional occurrence of bilateral RE - has already been reported [3-5], this is the first such case in which bilateral RE and FCD co-occur.