Acute necrotizing encephalopathy of childhood: typical findings in an atypical disease.

Acute necrotizing encephalopathy of childhood (ANEC) is a disease entity seen nearly exclusively in East Asian children that is characterized by multifocal, symmetric lesions involving the thalami, brainstem, cerebellum, and white matter. We present a child who developed dramatic neurologic symptoms following a viral prodrome. Serial MRI examinations demonstrated characteristic lesions of ANEC, while laboratory analyses revealed evidence of acute infection with human herpesvirus-6 (HHV-6). We highlight the MRI findings in both the acute and convalescent phases of ANEC, discuss the implications of neuroimaging on the child's clinical course, and emphasize the integral role of the radiologist in correctly diagnosing this rare disease.