The course of Multiple Sclerosis (MS) is incredibly diverse. "Aggressive" disease is characterised by a relapsing history that rapidly worsens physical and cognitive dysfunction, frequently in spite of treatment. Presentation of the case: There is a lack of standardisation in the diagnostic and management of aggressive Multiple Sclerosis (MS). There are currently no definite reports of ocrelizumab being used to treat tumefactive, breakthrough diseases. A 34 years old Caucasian lady was hospitalised after experiencing nausea, vomiting, and slight gait ataxia. Multiple demyelinating lesions in the brain were identified using Magnetic Resonance Imaging (MRI), many of which were infratentorial and displayed tumefactive appearance and gadolinium enhancement.