Myeloma of the central nervous system: association with high-risk chromosomal abnormalities, plasmablastic morphology and extramedullary manifestations.

Involvement of the central nervous system (CNS) by multiple myeloma, as defined by the detection of malignant plasma cells in the cerebrospinal fluid in the presence of suggestive symptoms, is considered extremely rare. We report on the characteristics of 18 such patients diagnosed and treated at the University of Arkansas over the last 10 years for an overall incidence of approximately 1%. Their evaluation revealed association of CNS involvement with unfavourable cytogenetic abnormalities (especially translocations and deletion of the chromosome 13), high tumour mass, plasmablastic morphology, additional extramedullary myeloma manifestations and circulating plasma cells. The presence of these features should alert clinicians to the possibility of CNS involvement. The outcome of these patients was extremely poor despite the use of aggressive local and systemic treatment including autologous stem cell transplants. Given this universally poor prognosis, the application of allogeneic transplants should be studied in this clinical setting.