Intravascular large B-cell lymphoma presenting as slowly progressive paraparesis with normal MRI features

Intravascular large B-cell lymphoma (IVLBCL) is a rare, high grade extranodal B-cell lymphoma, characterized by the proliferation of tumoral cells in the lumen of small vessels of several organs without the tendency for tumor formation in other areas usually affected by lymphomas, such as lymph nodes, bone marrow, or peripheral blood. Diagnosis is generally delayed by variable presentation with non-specific constitutional and neurological symptoms, lack of reliable ancillary tests and it is often obtained only at autopsy. We report a case of IVLBCL presenting with a slowly progressing isolated paraparesis without any evidence of spinal damage at MRI though neurophysiological examinations showed signs of spinal cord injury. Laboratory findings showed markedly elevated levels of lactate dehydrogenase, low albumin values, raised ESR, mild thrombocytopenia and progressive impairment of hepatic function. Bone marrow examinations and total body CT scans were negative. Although clinical history appeared too long, we considered the hypothesis of IVLBCL on the basis of the laboratory constellation and proposed a liver biopsy, but the patient refused the procedure. The diagnosis was confirmed only at autopsy. Our case should make us aware that the disease has to be considered in the differential diagnosis of unexplained paraparesis associated with elevated level of lactate dehydrogenase and only relatively non-specific laboratory findings even without any spinal cord abnormalities at MRI.