Multiple intracranial lesions with lung adenocarcinoma: A rare case of MOG- IgG-associated encephalomyelitis

Background: Myelin oligodendrocyte glycoprotein (MOG) is an important marker on the surface of oligoden- drocytes 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.