Cryoglobulinemic membranoproliferative glomerulonephritis associated with mucosa-associated lymphoid tissue lymphoma treated with rituximab.

Cryoglobulinemia and mucosa-associated lymphoid tissue (MALT) lymphoma are diseases characterized by B-cell dysregulation and overproduction of antibodies. Vasculitis and cutaneous manifestations are common, but renal involvement is rare. A 65-year-old woman with type 1 cryoglobulinemia and MALT lymphomas of the right lacrimal and parotid glands successfully treated by excision and chemoradiotherapy, presented with dyspnea on exertion, edema, and hematuria. Renal biopsy findings revealed type 1 cryoglobulinemic glomerulonephritis. She underwent treatment with high-dose oral prednisone and intravenous rituximab with subsequent return of creatinine to baseline levels. To our knowledge, this is the first report of a patient in whom type 1 cryoglobulinemia, multiple MALT lymphomas, and MPGN with IgM cryoglobulin deposits coexist. Evidence for rituximab is sparse with widely varying protocols and mixed results. There is a need for high quality evidence in the treatment of these conditions.