Abstract
Marginal zone B cell lymphomas are divided into nodal, extranodal and splenic types. Renal involvement by extranodal B cell lymphoma is extremely rare with an incidence of about 0.1%. We present a case of a 79-year-old Caucasian male with progressive renal failure and isolated left renal extranodal marginal zone lymphoma. Asymptomatic immunoglobulin (Ig) M monoclonal gammopathy along with bone marrow involvement by lymphoma was observed. Contemporary management options including radiotherapy (RT), chemotherapy, immune-modulating agents and novel chemotherapy-free regimens.