Four patients, ages 4, 6, 13, and 21 years, with life-threatening focal motor status epilepticus, normal pre-operative MRI, and focal cortical dysplasia defined only in the surgical specimens obtained by corticectomies, are reported from the Montreal Neurological Institute; Austin Hospital, Heidelberg, Australia; University of California, San Francisco; and Royal Children’s Hospital, Melbourne, Australia. Seizures began between 3 months and 18 years of age, and therapy-resistant focal status developed after 18 months to 3 years, resulting in persistent motor deficits. A total of 12 MRIs failed to reveal abnormalities. Ictal SPECT was positive in 2 patients. Seizures were controlled after surgery, and 2 patients were seizure-free. 
COMMENT. Neuronal migration disorder as a cause of focal motor status epilepticus or epilepsia partialis continua in a child may not be excluded by the MRI and may require surgical intervention for diagnosis and treatment.