Extension of syringomyelia to the cerebral hemispheres, termed syringocephaly, is rare.1,2 We report the case of a 50-year-old woman who had undergone repeated posterior fossa decompression for Chiari malformation type I with syringomyelia, resulting in foraminal arachnoiditis. Two years later, she presented with cerebellar ataxia revealing a holocord progression of the syringomyelia, extending to the cerebellar hemispheres (figure, A). Millimetric T2-weighed and CSF flow sequences confirmed communication between cavities (figure, B). A cysto-peritoneal shunt was performed. Follow-up at 1 year demonstrated a marked improvement of cerebellar signs and complete radiologic regression of the cerebellar syringocephaly (figure, C).