Opsomyoclonus is encountered as C/F of -

"At least 50% of children with opsoclonus-myoclonus have an underlying neuroblastoma." - Harrison Opsoclonus-Myoclonus Syndrome Opsoclonus is a disorder of eye movement characterized by involuntary, chaotic saccades that occur in all directions of gaze; it is frequently associated with myoclonus and ataxia. Causes of Opsoclonus-myoclonus Idiopathic Cancer-related (paraneoplastic) Cancers associated with opsoclonus-myoclonus are usually lung and breast cancers in adults and neuroblastoma in children.