Opsoclonus myoclonus syndrome, colloquially known as a disease of “dancing feet and dancing eyes,” is a dramatic neurologic syndrome characterized by the presence of opsoclonus and frequently diffuse or focal myoclonus, truncal ataxia, encephalopathy, and brainstem or other cerebellar manifestations. The disorder is most frequently autoimmune, parainfectious, and paraneoplastic in both adults and children but has also been seen to occur in metabolic and lesional brain disorders such as tumors or stroke.
Opsoclonus myoclonus often occurs as a remote immunologically-mediated effect of an otherwise occult neoplasm. Opsoclonus myoclonus syndrome is more common in children than adults. Fifty percent children will have opsoclonus myoclonus syndrome as a result of neuroblastoma, most commonly without an underlying onconeural antibody identified (14). In adults, the most common malignancies are small cell lung cancer, breast adenocarcinoma, and ovarian teratoma. A cancer is identified in 20% to 40% of cases, and onconeural antibodies are detected in only 11% of patients. However, a subset of patients, specifically women, with antineuronal nuclear autoantibodies type 2 (ANNA2; anti-Ri) have demonstrated this phenotype in association with an underlying breast adenocarcinoma, small cell lung cancer, or ovarian tumor.
Some patients show significant neurologic improvement with successful tumor therapy or immunotherapy, whereas others are left with permanent and severe neurologic disability despite treatment. The authors review the clinical features, autoimmune aspects, and practical patient management of paraneoplastic opsoclonus.
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• Most adults with paraneoplastic opsoclonus myoclonus may have diffuse or incomplete manifestation of both symptoms and may additionally have truncal titubation, ataxia, and other cerebellar impairments.
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• Additional symptoms that can occur include encephalopathy and brainstem dysfunction, and encephalopathy can be associated with a poor prognosis.
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• Adults with paraneoplastic opsoclonus myoclonus syndrome most frequently have underlying small cell lung carcinoma or breast adenocarcinoma.
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• No one specific onconeural antibody is putative in the development of adult-onset paraneoplastic opsoclonus myoclonus, but instead several onconeural antibodies, most commonly ANNA2.
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• The neurologic outcome of adults with paraneoplastic opsoclonus is variable; some patients improve dramatically with oncologic therapy and immunotherapy.
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• Although others are left with severe permanent neurologic disability, outcomes are likely dependent on rapid detection and management of disease.
Historical note and terminology
The term "opsoclonus" was first used by Orzechowski in 1927 in reference to chaotic, repetitive, rapid eye movements observed in several patients with nonepidemic encephalitis. At the bedside, opsoclonus is generally defined as involuntary, chaotic saccades in all planes (horizontal, vertical, torsional), worsened by attempts at voluntary saccades or fixation. In electro-oculographic recordings, opsoclonus is characterized by bursts of conjugate and dysconjugate saccadic oscillations without an intersaccadic interval. Opsoclonus occurs in association with numerous disorders in patients of all ages. Case reports of opsoclonus in adults with a variety of associated neoplasms date back more than 50 years. Paraneoplastic opsoclonus myoclonus is best described as syndromic and phenotypic description, rather than a unique disease, due to the number of heterogeneous neurologic diseases associated with the syndrome. As is common with paraneoplastic neurologic diseases, there is diversity in the neurologic presentations and underlying tumors seen with different autoantibodies.