Introduction
Opsoclonus-myoclonus syndrome (OMS) associated with neuroblastoma
(OMS-NB) is a refractory paraneoplastic syndrome presenting as
opsoclonus, myoclonus, ataxia, dysarthria, behavioral and cognitive
disorder. Although OMS-NB patients show good life prognosis [1], the
neurological prognosis is poor. OMS-related neurological symptoms often
remain even after tumor resection and inflict permanent neurological
sequelae, including developmental, cognitive, and behavioral deficits,
disturbing daily life in 30–70% of those patients. Some autoantibodies
such as anti-glutamate receptor δ2 (GluRδ2) antibody and oligoclonal
bands in cerebrospinal fluid (CSF) have been detected in OMS patients
continuously, even after tumor resection.[2,3] Therefore, humoral
autoimmunity has been considered the cause of OMS. Immunosuppressive
therapies, including glucocorticoid and intravenous immunoglobulin
(IVIg), have been reported as initial therapy[4], however
pathogenesis-based treatment strategies have not yet been established.
We encountered a pediatric patient presenting with OMS-NB who showed an
increased number of CD20-positive B cells in both CSF and neuroblastoma
tissue. Unbiased B-cell receptor (BCR) repertoire analysis followed by
next-generation sequencing revealed identical B-cell clone in both CSF
and tumor tissue in our patient.
This mechanism could facilitate
the establishment of novel treatment strategies for OMS-NB.