Fig. 1

a SWI on the first admission revealed low-signal intensity spotty lesions in the left cerebellar peduncle (arrow). b T2*WI on the first admission. Findings similar to those in Fig. 1a are present (arrow). c Contrast-enhanced MRI on the first admission showed no apparently enhanced lesions, including in the cerebellar peduncle. d SWI obtained three months after the first admission revealed de novo low-intensity spots in the medulla oblongata. e T2*WI obtained three months after the first admission. Findings are to those in Fig. 1d. f Contrast-enhanced MRI obtained three months after the first admission showed no apparently enhanced lesions. g SWI obtained one year after the first admission revealed spreading hypointensity- lesions adjacent to the fourth ventricle (arrows). h T2*WI obtained one year after the first admission. Findings similar to those in Fig. 1g are present. i Contrast-enhanced MRI obtained one year after the first admission showed a slightly enhanced lesion around the fourth ventricle. j SWI on the second admission revealed expanding lesions of the pons and right cerebellar peduncle (arrows). k T2*WI on the second admission revealed findings similar to those in Fig. 1k. l Contract-enhanced MRI on the second admission showed an expanded enhanced lesion around the fourth ventricle