Opsoclonus-myoclonus is a rare syndrome characterized by multidirectional chaotic eye movements, myoclonus and ataxia. In children, it could be a paraneoplastic syndrome in association with neuroblastoma, usually with a high survival rate, but having a high frequency of neurologic and psychologic sequelae.
Objectives: The aim of this study was to describe oncologic outcome (prospectively) and neurologic outcome (retrospectively) in children with non-metastatic neuroblastoma, and to determine its best treatment.
Patients and methods: Data were collected on 21 children diagnosed with localized neuroblastoma and opsoclonus-myoclonus between 1990-1999 from the French Society of Pediatric Oncology institutions.
Results: Median age at diagnosis was 18 months. Location of the tumor was abdominal in 14 cases, thoracic in three cases, pelvic in three cases, and cervical in the last case. There was a majority of small tumors with a maximal diameter < 5 cm in 13 cases. Only four tumors were initially considered as unresectable tumors and received first-line chemotherapy. Complete macroscopic resection was performed in 20 cases (four after primary chemotherapy). Nine children received chemotherapy. Twenty children remained in first complete remission, and one relapsed and died (the unique NMYC amplified case). Treatment for opsoclonus-myoclonus varied widely. Only one child received no medical treatment for opsoclonus-myoclonus, because of complete resolution of neurologic symptoms after exclusive surgery. The following agents were used: corticosteroids in 18 cases, intravenously immune globulin in five cases, and antiepileptic drugs in seven cases. Ten patients experienced relapses of opsoclonus-myoclonus symptoms, mainly related to the decrease of steroid therapy (5/10). Ten of 16 assessable children had persistent neurologic deficits including speech delay or cognitive deficits (8/16), ataxia (6/16), motor delay (2/16), and behavioral problems (2/16). There is no correlation between neurologic outcome, and either age at diagnosis or duration of neurologic symptoms, or type of treatment of the tumor, particularly chemotherapy.
Conclusion: Persistent neurologic deficits are characteristic for children with neuroblastoma and opsoclonus-myoclonus. Neurologic outcome seems unrelated to the treatment of neuroblastoma, which should exclusively be conducted according to oncological criteria. The treatment of opsoclonus-myoclonus should be standardized, mainly based on high-dose hydrocortisone, with a very low decreasing dosage, associated to intravenously immune globulin in severe cases. A biological immunologic work-up of the disease and cautious neurologic and psychologic standardized follow-up should be performed.