Neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome: an important yet overlooked diagnosis in pediatric ataxia

The cohort included four girls and three boys, aged 18-36 months (median 31). All had a history of infection and/or vaccination preceding symptom onset. Ataxia was the most common initial symptom (6/7, 85.7%), followed by behavioral disturbances and sleep disorders (5/7, 71.4% each). At presentation, opsoclonus was present in two patients, which was initially misdiagnosed as nystagmus. All but one patient had opsoclonus during the disease course. Neuroblastomas were located in abdominal (n=4), thoracic (n=1), and sacral (n=2) regions; all tumors measured.