Treatment of Bing–Neel syndrome with first line sequential chemoimmunotherapy

Abstract Rationale: Bing–Neel syndrome (BNS) is a rare manifestation of Waldenström macroglobulinemia (WM) with <200 cases reported in the literature. Herein, we describe a case of newly diagnosed BNS treated with a novel therapeutic strategy. Patient concerns: A 67-year-old woman diagnosed with asymptomatic WM 3 years ago presented with gradual vision deterioration the past 3 months. Ophthalmologic examination revealed bilateral reduction in visual acuity (7/10) and bilateral optic disc swelling which was more prominent in the left eye. Diagnoses: Brain imaging revealed bilateral swelling of optic nerves extending from the retina to the optic chiasm and swelling of the left optic tract. Patchy enhancement of optic nerves was also shown upon intravenous contrast administration. Flow cytometry of the cerebrospinal fluid (CSF) revealed the presence of κ-light chain restricted, monoclonal B-lymphocytes. CSF protein electrophoresis showed a monoclonal band in the gamma region and immunofixation was positive for immunoglobulin M and kappa light chain. Thus, the diagnosis of BNS was established. Interventions: The patient was initially treated with intrathecal methotrexate and systemic chemotherapy. Following 2 intrathecal methotrexate infusions, CSF flow cytometry did not detect any cells, whereas the patient reported improvement in visual acuity. Therefore, we opted to start maintenance treatment with IV rituximab and per os ibrutinib. Outcomes: Following 1 year posttreatment initiation, visual problems have resolved completely and the patient remains on hematologic and imaging complete response. Lessons: We propose a novel sequential chemoimmunotherapy approach for BNS treatment aiming both at rapid disease control and deep and durable remission with minimization of induced toxicity.