Successful Treatment of Bing-Neel Syndrome Accompanying Waldenström's Macroglobulinemia with R-MPV: A Case Report.

Waldenström's macroglobulinemia (WM) is a neoplasm of lymphoplasmacytic cells that produces monoclonal IgM protein. Although hyperviscosity syndrome is a common feature of WM, central nervous system (CNS) involvement in WM is rare and is known as Bing-Neel syndrome. A 60-year-old woman was referred to our hospital with bed-bound polyneuropathy, edema, splenomegaly, IgM-λ-type monoclonal protein and CD20-positive lymphocyte infiltration in the bone marrow. She was diagnosed with WM accompanying POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) and was treated with rituximab and thalidomide. She achieved partial remission of WM, and thalidomide was continued for POEMS syndrome. She visited our outpatient clinic 6 years later with sudden onset of vertigo and nausea. Magnetic resonance imaging (MRI) revealed a low-density area 4 cm in diameter in her right cerebrum and right mid-brain and she was referred to our hospital. Pathological analysis of brain biopsy samples revealed diffuse large B-cell lymphoma (DLBCL) in the CNS. Nucleic acid sequence analysis of the VDJ region using DNA obtained from the original WM tumor cells and brain tissue revealed that the DLBCL cells were derived from the original WM malignant lymphoma cells. She received five cycles of rituximab, methotrexate, procarbazine, and vincristine (R-MPV) therapy and 23.4 Gy of whole-brain irradiation followed by two cycles of high-dose cytarabine, which resolved her neurological symptoms in association with reduction of IgM levels to 367 mg/dL. MRI and computed tomography of the brain demonstrated complete remission of her CNS lymphoma.