Intravascular lymphoma presenting as a longitudinally-extensive myelitis: diagnostic challenges and etiologic clues.

Intravascular lymphoma is a rare disorder that commonly involves the central nervous system. Neurologic involvement may be the presenting and only manifestation. Identifying intravascular lymphoma as the cause of neurologic disease is diagnostically challenging. We report an elderly woman presenting with subacute onset paraparesis due to spinal cord involvement by an intravascular lymphoma. Progressive worsening was associated with extension of a longitudinally-extensive thoracic intramedullary spinal cord lesion. Extensive investigations failed to provide a diagnosis in life and repeated empiric therapeutic trials were unsuccessful. Diagnostic confirmation was postmortem. A longitudinally-extensive spinal cord lesion has a broad differential diagnosis. Intravascular lymphoma should be considered particularly in older individuals. The presence of coexisting hematologic abnormalities should prompt consideration of a bone marrow biopsy. Early diagnosis may direct therapy and lead to a more favorable prognosis.