Assessment of concurrent neoplasms and a paraneoplastic association in MOGAD.

Cases of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) co-occurring with neoplasms have been reported. In this international, retrospective cohort study in South Korea and the USA, 16 of 445 (3.6%) patients with MOGAD had concurrent neoplasm within 2 years of MOGAD onset, resulting in a standardized incidence ratio for neoplasm of 3.10 (95% confidence interval [CI], 1.77-4.81; P < 0.001) when compared to the age- and country-adjusted incidence of neoplasm in the general population. However, none of the nine tumor tissues obtained demonstrated MOG immunostaining. The slightly increased frequency without immunohistopathological evidence suggest with true paraneoplastic MOGAD is extremely rare.