Eosinophilic granuloma commonly involves bone; however, neurologic deficit secondary to bony or extraosseous extension of disease of the spine is rare. We report a case of eosinophilic granuloma of the cervicothoracic junction in a 10-year-old boy and demonstrate the value of magnetic resonance imaging in defining the initial extent of the disease and following the resolution of the extraosseous involvement after therapeutic intervention.