Opsoclonus-myoclonus syndrome with abnormal single photon emission computed tomography imaging.

The single photon emission computed tomography (SPECT) findings in 2 patients with opsoclonus-myoclonus syndrome (OMS) who had similar symptoms in the acute stage of the disease are described. In 1 patient with encephalitis, SPECT showed increased blood flow in most of the cerebellum; the highest accumulation of the radiotracer was found in the cerebellar vermis and neighboring structures. These changes disappeared with clinical improvement. In the other patient with chronic OMS, SPECT demonstrated hypoperfusion in most of the cerebellum. Our results suggest that the cerebellum, particularly its middle portion, is involved in the generation of OMS. SPECt is a useful method that enables us to detect in vivo functional impairment in patients with OMS.