Early Detection and Treatment of Neuroblastic Tumor with Opsoclonus-Myoclonus Syndrome Improve Neurological Outcome: A Review of Five Cases at a Single Institution in Japan.

INTRODUCTION: Opsoclonus-myoclonus syndrome (OMS) is a paraneoplastic neurological disorder associated with neuroblastic tumor (NT) in childhood. Half of patients have neurological sequelae after the neurological and oncological treatment. We reviewed the neurological and oncological outcomes of NT with OMS, and discussed whether the treatment of NT would contribute to improving the neurological prognosis.

METHODS: We retrospectively assessed NT patients with OMS from January 2001 to December 2013 at a single institution in Japan. Demographic data, neurological and oncological status, histopathology, treatments, prognosis, and diagnosis and treatment timing were retrospectively reviewed from the records. The timings assessed were the interval between OMS onset and NT detection, initial NT therapy, and initial OMS therapy, the interval between NT therapy and OMS remission, and duration of OMS.

RESULTS: A total of 73 patients with NT were treated during the study period, and 5 of 73 patients were diagnosed as having NT with OMS. The median age at onset of OMS was 22 months (range, 18-30 months). The median age at detection of NT was 29 months (range, 21-33 months). Three of five cases showed no uptake on meta-iodobenzylguanidine scintigraphy. The tumor histopathology was neuroblastoma in two patients, ganglioneuroblastoma in two patients, and ganglioneuroma in one patient. Primary resection was performed in three cases. All patients survived. Two of five cases presented with atypical neurological symptoms without opsoclonus. The initial neurological therapy was started within a mean of 20 days (range, 3-76 days) from the onset of OMS in all cases. Four patients received intravenous immunoglobulin, and one with persistent neurological problems received rituximab. Neurological symptoms resolved in three cases. The mean interval between the onset of OMS and the detection of NT in case without neurological sequelae was 57 days (range, 25-113 days), while in case with neurological sequelae it was 365 days (range, 271-458 days). The mean interval between onset of OMS and initial therapy for NT in case without neurological sequelae was 88 days (range, 47-145 days), while in case with neurological sequelae it was 389 days (range, 292-486 days).

CONCLUSION: The interval between the onset of OMS and the detection and initial therapy of NT tended to be longer in patients with neurological sequelae than in those without neurological sequelae. This study suggested that early detection and treatment of NT with OMS might improve the neurological outcomes.