Cauda equina lymphoma: a case report including postmortem examination.

While primary central nervous system (CNS) lympho­ mas are rare, aggressive B­cell lymphomas may second­ arily involve the CNS in up to 25% of patients with risk factors, particularly multiple extranodal sites of dis ease.1,2 B­cell lymphomas very rarely present solely with lumbosacral neurologic signs consistent with cauda equina syndrome. Detection of lymphoma with CNS involvement can be difficult, in spite of advances in cerebrospinal fluid (CSF) analysis and imaging techniques. Herein, we describe a case of fatal large B­cell lymphoma presenting with cauda equina syndrome, without discernible nodal disease but with diffuse extranodal involvement at autopsy. We review radiographic and pathologic features of cauda equina lymphomas in light of 19 cases reported in the last 2 decades.3­21