Late detection of neuroblastoma in a patient with prolonged cerebellar ataxia without opsoclonus.

A 19-month-old boy presented with acute-onset cerebellar ataxia following immunisation. Ataxia was prolonged with a fluctuating course over a period of two years. Opsoclonus was never observed. Extensive diagnostic studies were negative during this time. Finally, a neuroblastoma was discovered. Ataxia disappeared completely during polychemotherapy. This report suggests that occult neuroblastoma must be considered in any child with unexplained prolonged cerebellar ataxia. Specific investigations are recommended for such cases.