WM is a lymphoplasmacytic lymphoma associated with IgM paraproteinemia that encompasses various neurological complications commonly appendicular/gait ataxia and cranial neuropathies. Lymphoplasmacytic cell infiltration in the central nervous system known as Bing-Neel syndrome is relatively a rare complication. From 1995-2014 there has been only 44 cases of BNS documented and only a handful of cases since then.

Serum viscosity was 1.2 centipoises, serum immunofixation revealed IgM of 1898 mg/dl, normal IgA and IgG titers. Initial CSF analysis revealed protein of 366 mg/dl, WBC of 416/ cu mm

(92% lymphocytes), elevated IgA (3.2mg/dl) and IgM titers (>25mg/dl). A second CSF analysis showed opening pressure of 20 mmHg, WBC 82/ cu mm (95% Lymphocytes). CSF cytometry showed kappa restricted B cells (CD5- CD10+ CD19+ CD 20+ CD22+ CD38+ and CD45+). CSF sample was inadequate for CSF immunofixation. MRI with gadolinium showed abnormal contrast enhancement within the internal auditory canals, trigeminal nerves, along the cisternal segments of the oculomotor nerves, and extraocular muscles strongly suggestive of leptomeningeal carcinomatosis. After 2 doses of intrathecal methotrexate and chemotherapy (obinutuzumab and bendamustine), all symptoms resolved.