Primary diffuse large B-cell lymphoma (DLBCL) of cauda equina is a very rare manifestation of neurolymphomatosis. A 52-year-old female presented with progressive symptoms of left lower extremity burning sensation. After initial conservative management with no improvement, MRI of the lumbosacral spine showed pathologic enhancement and thickening of cauda equina nerve roots. Examination of cerebrospinal fluid, coupled with flow cytometry, was diagnostic of DLBCL. Clinicians and pathologists should be aware of this unusual and challenging clinical presentation of DLBCL.