Dense deposit disease in association with monoclonal gammopathy of unknown significance.

Several renal pathologic entities have been reported in patients with lymphoplasmacytic disorders with their typical excess immunoglobulin production. We report dense deposit disease in a patient who was discovered to have an IgG kappa monoclonal protein without clinical evidence of underlying lymphoplasmacytic malignancy during investigation for chronic renal failure with associated nephrotic range proteinuria. This case is unusual since dense deposit disease occurs only rarely in older patients and has not been reported in association with monoclonal gammopathy of unknown significance. Because of the diversity of renal lesions associated with lymphoplasmacytic disorders, renal biopsy is necessary to assess the type of renal lesion in this patient population.