Multiple Intracranial Lesions with Lung Adenocarcinoma: A Rare Case of MOG-IgG-associated Encephalomyelitis

Abstract Background Myelin oligodendrocyte glycoprotein (MOG) is an important marker on the surface of oligodendrocytes and is associated with many demyelinating diseases. Recently, MOG-IgG-associated encephalomyelitis (MOG-EM) has been proposed as a disease entity with a preliminary diagnosis standard. Some patients with lung cancer have been reported to be seropositive for onconeural antibodies; however, lung cancer cases with MOG-EM have not been previously reported. Methods We report the case of a patient with lung adenocarcinoma with multiple intracranial lesions found during molecular targeted therapy. Results The patient tested positive for MOG antibody in her cerebrospinal fluid, and the therapeutic effect of steroids was excellent. Conclusion This is the first reported case of MOG-EM coincident with lung cancer in a patient with multiple intracranial lesions. When patients present with a history of malignant tumors or suspected paraneoplastic neurological syndrome, clinicians should also be alert to the presence of other autoimmune antibodies such as MOG-IgG to avoid treatment delay.