Case Presentation: A 66 year-old woman with Waldenstrom macroglobulinemia (WM), hypertension, and hyperlipidemia presented with acute altered mental status. She had been diagnosed with WM by bone marrow biopsy and was treated with rituximab, then maintained on thalidomide until 2 months prior to presentation. Her mother had suffered from multiple myeloma. Vital signs were normal. [...]