Tumefactive multiple sclerosis comprises a rare subset of multiple sclerosis that often poses a diagnostic challenge to physicians. It is unique in its presentation as a solitary lesion, usually larger than 2 cm, with surrounding vasogenic edema, commonly mimicking a primary intracranial malignancy. We present a case of a 25-year-old female with no significant past medical history who presented to our institution with homonymous superior quadrantanopia. During her admission, she underwent a magnetic resonance imaging (MRI) of the brain, which revealed a large lesion in the left temporal area surrounded by marked edema. A thorough workup revealed a diagnosis of tumefactive multiple sclerosis. Subsequently, she was initiated on intravenous immunoglobulin rather than stress dose steroids, given the concern for a superimposed infection. Interestingly, the patient had a paradoxical progression of her symptoms as well as expansion of the vasogenic edema on a repeat MRI. In our case, we highlight the key differences in tumefactive multiple sclerosis diagnosis and management.