A syndrome of chronic partial epileptic seizures attended by progressive focal sensorimotor neurological deficit and cognitive decline, and with neuropathological features of a localized chronic encephalitis, was first defined by Rasmussen and his colleagues in 1958 [1]. Diagnosis of Rasmussen's syndrome (RS) is suggested by the typical clinical features of epilepsia partialis continua, episodes of complex partial status and intractability to standard anti-epileptic drugs. Support for the diagnosis is provided by interictal electroencephalographic evidence of multiple independent lateralized epileptiform abnormalities, and radiological evidence of focal brain atrophy. T2-weighted magnetic resonance imaging may demonstrate high intensity signals in the white matter, consistent with gliosis, and positron emission tomography and single photon emission computed tomography may demonstrate localized changes in glucose metabolism and cerebral perfusion. Ultimately, however, diagnosis is dependent on the neuropathological appearances at brain biopsy or hemispherectomy. These show some variability [2], ranging from an ongoing inflammatory process with microglial nodules, neuronophagia, perivascular lymphocytic cuffing and glial scarring to “non-specific” changes with very few or no microglial nodules, mild perivascular inflammation and various degrees of neuronal loss and glial scarring.