Favorable prognosis for survival in children with coincident opso-myoclonus and neuroblastoma.

Case reports of 28 neuroblastoma patients who had opso-myoclonus as their presenting feature are reviewed. As compared with the 30%-34% two-year survival rate for the overall population of patients with neuroblastoma, those who exhibited the opso-myoclonus/neuroblastoma combination had a tumor-free two-year survival rate of 89.3%. This excellent prognosis may be explained partially by earlier diagnosis and a higher percentage (71% vs. 33%) of patients with Stage I, II, and IV-S disease in the opso-myoclonus sub-group. However, these factors are not, of themselves, sufficient to explain totally the differences in survival rate since five of seven patients with Stage III-IV disease also exhibited long-term survival. This raises the question as to whether the neurologic dysfunction in these patients is pathogenetically related to an unknown factor (possibly autoimmune) which also controls growth and spread of the tumor.