Spinal epidural lipomatosis (SEL) is a rare condition of adipose tissue accumulation in the epidural space. A total of 2,309 subjects from March 2011 to April 2012 were studied. We found different morphologic “variants” of dural sac compression in grade III. The trifid type, resembling the letter “Y", was the most common form. The round type and the localized mass in lateral recess were seen in other cases. Surgical decompression was performed regardless of morphologic variants in SEL grade III with neurologic symptoms. All patients recovered from neurologic symptoms. In subjects who received adequate conservative treatment, decompressive surgery could be helpful in treatment of SEL grade III with neurologic symptoms.