Glioma-like inflammatory demyelinating lesions can be found in patients with pre-diagnosed multiple sclerosis, but they have also been described as an isolated disease entity. The initial diagnostic work-up usually includes a biopsy for histopathological analysis. However, even after unambiguous histopathologic classification, tumefactive lesions pose a therapeutic challenge. Until now, there have been no guidelines on how to treat patients with these rare and extreme lesion phenotypes. Here we report a patient with a relapsing unifocal tumefactive demyelinating lesion. The patient initially showed a good response to steroid treatment, with full clinical recovery. However, after relapse of the same lesion, recovery was incomplete. Although immunosuppression was initiated, the patient presented with subsequent further deterioration. Only maximal escalation of immunosuppression was able to stop the inflammatory activity. Due to the length of time of the step-wise escalation treatment however, the lengthy lesion activity led to irreversible tissue destruction and residual non-remitting disability. Early aggressive treatment with an induction therapy regimen might be more appropriate for these rare and often strongly disabling lesion subtypes.