Primary cauda equina lymphoma diagnosed by nerve biopsy: A case report and literature review.

Primary cauda equina lymphoma (CEL) is a rare malignant tumor among various neoplasms that affects the cauda equina nerve roots. The present case report described the case of a 65-year-old man who presented with cauda equina syndrome with progressive motor palsy in the legs and gait disturbance over the last 5 months. Magnetic resonance (MR) images showed enlargement of the cauda equina occupying the dural sac from the L1-S1 level with isointensity to the spinal cord signal on both T1- and T2-weighted imaging. Enhancement of the cauda equina was seen on contrast MR images. On F-18 2-fluoro-2-deoxy-glucose positron emission tomography examination, diffuse accumulation of 2-fluoro-2-deoxy-glucose was observed in the cauda equina with a maximum standardized uptake value of 4.9. Based on elevation of soluble interleukin 2 receptor in cerebrospinal fluid and a biopsy of the enlarging cauda equina, a diagnosis of CEL of the diffuse large B-cell type was made. The present case report provided a detailed case discussion and a review of the available literature on this rare entity, focusing on clinical characteristics and imaging of primary CEL.