Spinal epidural lipomatosis (SEL) is a rare condition characterized by overgrowth of normal adipose tissue in the extradural space within the spinal canal that can lead to significant spinal cord compression. It is most commonly reported in patients receiving chronic glucocorticoid therapy. Other causes can include obesity and hypercortisolism. Occasionally, idiopathic SEL will occur in patients with no known risk factors, but cases are more generally reported in obesity and males. We present the case of a 35 year-old non-obese woman found to have rapidly progressive SEL that was not associated with any of the common causes of the disorder.