Opsoclonus-myoclonus syndrome associated with a nasopharyngeal tumor in an adult: a case report

INTRODUCTION Opsoclonus-myoclonus syndrome is a rare autoimmune syndrome usually seen in children and very rarely in adults. It typically presents with a triad of opsoclonus, myoclonus and ataxia, and is most often associated with a tumor or after an infection or vaccination. Around half of all adult cases are paraneoplastic in origin, and isolated case reports include associations with lung, breast and ovarian cancers. To the best of our knowledge, this is the first-ever reported case of paraneoplastic opsoclonus-myoclonus syndrome occurring in association with a nasopharyngeal carcinoma. CASE PRESENTATION A 50-year-old British Caucasian woman presented with left-sided otalgia and subjective hearing loss. Over the coming weeks she developed subacute confusion and dizziness, leading to recurrent falls. Her clinical examination revealed opsoclonus, myoclonus and signs of cerebellar dysfunction. Subsequent magnetic resonance imaging revealed a left-sided nasopharyngeal carcinoma, which was confirmed on biopsy. A tapering dose of steroids and a five-day course of intravenous immunoglobulins, followed by a combination of chemo-radiotherapy for the nasopharyngeal carcinoma, led to a significant clinical improvement. At six months follow-up she had no signs of focal neurological deficit, apart from the inability to tandem walk. We believe that the typical clinical features, presence of a tumor and response to treatment support a paraneoplastic aetiology. CONCLUSIONS We show that a nasopharyngeal carcinoma can be associated with adult onset opsoclonus-myoclonus syndrome. Both neurologists and otorhinolaryngologists must be aware of such a presentation. Prognosis of the syndrome depends on early and adequate management of the tumor, therefore prompt identification of the syndrome and the underlying tumor is essential.