Opsomyoclonus (OMS), also known as dancing eyes-dancing feet syndrome and opsoclonus-myoclonus syndrome, is a clinical syndrome which has a strong association with neuroblastoma.
The “opso-“ refers to the presence of intermittent jerky eye movements (dancing eyes) and the “myoclonus” to myoclonic jerks and cerebellar ataxia (dancing feet). Although only 2% of patients with neuroblastoma present with opsomyoclonus, up to 50% of patients with opsomyoclonus are ultimately found to have neuroblastoma .
The implication is that a child found to have opsomyoclonus must be investigated thoroughly for otherwise occult neuroblastoma. In adults, autoimmunity secondary to infectious events rather than paraneoplastic phenomena is more common overall. Among paraneoplastic etiologies in adults with OMS, small cell lung cancer is the most common.
While the pathophysiology is unknown, OMS is felt to be related to autoimmunity. As a result of cerebellar Purkinje cell dysfunction, oculomotor neurons of the caudal fastigial nucleus of the cerebellum become progressively disinhibited. Anti-neuronal and anti-Purkinje cell antibodies have been implicated in OMS, however, they are not universally isolated in patients with OMD presentations .
A 2004 working group proposed the following clinical diagnostic criteria comprising three of the following four features :
- ataxia and/or myoclonus
- behavioral changes or sleep disturbances
- diagnosis of neuroblastoma
Treatment and prognosis
If neuroblastoma is found in a patient with opsomyoclonus, it is generally small with relatively favorable histology and the prognosis, in terms of survival, is very good. The neurologic symptoms may be treated with corticosteroids and/or ACTH, but often persist despite the medical treatment and surgical resection .