MOG antibody-positive patients meeting diagnostic criteria for MS: is it MOGAD with an MS-like phenotype or true MS?

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a recently recognized disorder distinct from multiple sclerosis (MS) and neuromyelitis optica spectrum disorder. The introduction of diagnostic criteria for MOGAD in 2023 marked a significant advance, providing high diagnostic accuracy for typical cases. However, challenges arise when patients test positive for MOG antibodies while also meeting the 2017 McDonald criteria for MS. These cases present a diagnostic dilemma, as they blur the lines between MS and MOGAD, complicating treatment decisions. This review addresses the diagnostic and management challenges faced by these patients, highlighting recent studies that underscore the difficulty in distinguishing between these two diseases and offering insights into how to approach these ambiguous cases.