Central Nervous System Involvement by Waldenstrom Macroglobulinemia: A Case Report of the Bing–Neel Syndrome

Bing–Neel syndrome (BNS) is a rare complication of Waldenstrom macroglobulinemia (WM) defined by a lymphoplasmacytic infiltration of the central nervous system (CNS). Patients present with a range of neurologic symptoms of variable severity. Diagnosis requires a low threshold of suspicion and is considered in WM patients with unexplained neurologic symptoms. It can occur in the presence of quiescent serum markers of WM. Direct CNS tissue biopsy should be pursued if feasible and remains the gold standard for diagnosis. No standard of care treatment exists, but expert guidelines suggest intravenous chemotherapy in standard dose or high-dose regimens or use of oral ibrutinib. Consideration is also made for intravenous rituximab, intrathecal therapies, and autologous stem cell transplantation. Patient factors and tolerability should drive decisions regarding treatment choice in this arena, given a lack of data for standard frontline therapy.