NCMP-04. OPSOCLONUS-MYOCLONUS SYNDROME ASSOCIATED WITH CONTACTIN-ASSOCIATED PROTEIN-LIKE 2 AUTOANTIBODY IN THE SETTING OF NON-SMALL CELL LUNG CARCINOMA

Abstract

Abstract INTRODUCTION Opsoclonus–myoclonus syndrome (OMS) is a rare neurological disorder characterized by spontaneous multidirectional saccadic eye movements, myoclonus, and ataxia. It is suspected to be an autoimmune mediated process precipitated by a paraneoplastic or infectious trigger. Among the pediatric population, OMS is often associated with neuroblastoma and anti-Hu antibody. Paraneoplastic syndromes in adults manifesting as OMS are most commonly described in breast, gynecological and small cell lung cancer with associated anti-neuronal antibodies (ANNA-2; anti-Ri). We describe the first case of OMS associated with lung adenocarcinoma and Contactin-associated protein-like 2 (Caspr2) antibody. CASE REPORT: A 46-year-old-woman with history of limited small cell lung cancer (SCLC) status-post chemotherapy with cisplatin and etoposide and prophylactic whole brain radiation, presented with new onset gait instability, nausea, vomiting, vertigo, and opsoclonus. Two months prior to her presentation, a chest computed topography (CT) revealed no evidence of recurrent disease. Brain MRI revealed T2 hyperintensities in the white matter and central pons presumably related to chronic small vessel ischemic changes, unchanged from prior imaging. CSF studies revealed normal cell count, glucose, and protein. Gram stain, culture and meningoencephalitis panel were negative. Her paraneoplastic panel revealed a positive Caspr2 antibody. A repeat CT chest for cancer surveillance revealed a new lung mass. Immunotherapy treatment included plasmapheresis, corticosteroids, and intravenous immunoglobulin therapy. She underwent a biopsy of the new pulmonary lesion and the pathology was consistent with non-small cell lung carcinoma. Her symptoms slowly improved after treatment. Unfortunately, her disease progressed on repeat PET scan despite surgical resection of the lung mass. She ultimately elected for hospice. CONCLUSION We report a novel antibody, Caspr2, occurring in association with paraneoplastic OMS. While SCLC is the most common neoplasm associated with OMS among adults, non-small cell lung carcinoma should be considered. Prompt immunotherapy and neoplasm treatment may result in improvement.