Plasma cell neoplasm in conjunction with glioblastoma of the conus medullaris.

We report a plasma cell neoplasm in conjunction with a glioblastoma multiforme (GBM) of the conus medullaris in a 42-year-old man. Glioblastoma is a World Health Organization (WHO) grade IV neoplasm that requires surgical intervention, radiation, and possibly chemotherapy. Astrocytomas of the spinal cord are rare neoplasms, with intramedullary glioblastomas comprising only 1% to 3%. Plasma cell neoplasms result from monoclonal proliferation of mature B cells; they have been reported as a primary malignancy with gliomas arising after treatment. Secondary plasma cell neoplasms arising within glioblastomas have not previously been described. However, there have been reports of glioblastomas related to other plasma cell and hematopoietic diseases such as Waldenstrom's macroglobulinemia and myeloid sarcomas.