Multiple myeloma with massive Bence Jones proteinuria and preservation of renal function

The case history of a patient having multiple myeloma with a remarkably high level of Bence Jones proteinuria (more than 20 g/day) is presented. The patient has responded well to therapy, and at no stage has he shown impairment of renal function as determined by creatinine clearance studies. A review of published reports has shown that such marked Bence Jones proteinuria at presentation is rare and is usually accompanied by renal impairment and a short survival. Additional presentation data from selected patients in the MRC First Myelomatosis Trial is presented. This suggests a higher incidence of marked Bence Jones proteinuria, and underlines the lack of correlation between the quantity excreted and the degree of renal impairment. The mechanisms by which Bence Jones protein may cause renal damage are discussed.