Neurolymphomatosis in the cauda equina diagnosed by an open biopsy

Neurolymphomatosis is a rare form of extranodal malignant lymphoma defined as the infiltration of malignant lymphocytes into the central or peripheral nerve. We herein report a case of neurolymphomatosis in the cauda equina diagnosed by an open surgical biopsy. He presented with muscle weakness, atrophy, numbness and hypoesthesia in the bilateral lower extremities with the accumulation of¹⁸fluoro-2-deoxyglucose (FDG) in the bilateral cauda equina. Cerebrospinal fluid cytology (three times) and flow cytometry (two times) and biopsies of the left sural nerve, bone marrow, paranasal sinus and left testis were all negative for malignancy, so finally we performed a surgical open biopsy of the cauda equina by laminectomy and diagnosed him with diffuse large B-cell lymphoma in the cauda equina. He was successfully treated with the disappearance of the FDG accumulation for a long time. The present case suggested that an early open biopsy of the cauda equina may be considered for cases of suspected neurolymphomatosis in the cauda equina for a good outcome.