A Unique Case of Encephalopathy with an Elevated IgG-4 and Extremely High Interleukin-6 Level and Delayed Myelodysplastic Syndrome

We herein report a 75-year-old man who developed disturbed consciousness with polynuclear cell dominant pleocytosis and low glucose extremely high interleukin (IL)-6 levels in his cerebrospinal fluid. The biopsy specimen from right supraclavicular lymph node showed the infiltration of inflammatory cells positive for IgG, IgG4 IL-6. Prednisolone azathioprine administered under suspicion IgG4-related disease (IgG4-RD) or multicentric Castleman's (MCD) successfully remitted symptoms. However, he myelodysplastic syndrome (MDS) died 18 months later. IL-6 may have been related to rare neurological manifestations development MDS present case.