Schilder disease, also termed diffuse myelinoclastic sclerosis, is characterized by a large demyelinating lesion involving 1 or both sides of the centrum semiovale of the cerebral hemispheres. It often presents with tumorlike features and poses a diagnostic challenge. Schilder disease can be monophasic or relapsing, and disease-modifying therapy for the latter scenario is largely empirical. Here, we report a 14-year-old girl with relapsing Schilder disease within 1 year after disease onset. She has been followed-up for nearly 10 years and remains in sustained remission ever since interferon-b therapy was prescribed after the second attack. In this case study, it is suggested that interferon-b may induce long-term remission in relapsing Schilder disease and is therefore worth considering in this regard.