Case of mononeuritis multiplex onset with rituximab therapy for Waldenström's macroglobulinemia.

Waldenström's macroglobulinemia (WM) is a lymphoplasmacytic disorder with associated monoclonal gammopathy. A wide variety of neuropathies can be associated with WM, but most commonly it is a mild length-dependent sensory neuropathy of unclear etiology. Rituximab is a monoclonal antibody which suppresses mature B-cell populations. It has increasingly been used in wide applications including WM, especially in those cases with severe neuropathy. The highlighted case provides an example of rituximab treatment complication in a WM patient with mild sensory neuropathy that evolved to multiple mononeuropathies with features of systemic vasculitis and unusual conversion of type I to type II cryoglobulinemia.