This is a case of Opsoclonus Myoclonus Ataxia Syndrome. A 14-month-old girl presented with abnormal eye movements and ataxia. On evaluation, she had opsoclonus, axial and appendicular ataxia, head titubation, occasional myoclonic jerks, as well as sleep disturbance and irritability. MRI of the abdomen and pelvis demonstrated a right suprarenal mass concerning for neuroblastoma. This constellation of symptoms is consistent with opsoclonus myoclonus ataxia syndrome, which is an immune-mediated condition. 50% of patients with opsoclonus myoclonus ataxia syndrome have associated neuroblastic tumors (a common example is neuroblastoma). Removal of the tumor, if present, along with early and aggressive immunotherapy, such as IVIG, high-dose steroids, and rituximab, helps to improve motor and cognitive outcomes long-term.
