Abstract: Objective To compare clinical features of multiple myeloma cast nephropathy（MM-MCN）and myeloma amyloidosis (MM-AL) and to evaluate the prognosis of MM-MCN. Methods The clinical characteristics of patients biopsy-proved MM-MCN and MM-AL over 5 years at Peking Union Medical College Hospital were collected. The hematologic and renal responses of MM-MCN patients after chemotherapy were also reviewed. Results The duration of renal involvement was shorter in MM-MCN（n=10）than that in MM-AL （n=13）(p＜0.05). The nephrotic syndrome of MM-MCN was less frequent than that of MM-AL (p＜0.05). The hemoglobin levels were lower in MM-MCN than those in MM-AL (p＜0.001) while the serum creatinine levels were higher in the former than those in the latter (p＜0.001).The percentage of bone marrow plama cell and 24 h urine light chain level in MM-MCN group were higher than those in MM-AL group（both p＜0.05）.Ten MM-MCN patients all manifested acute renal injury at the time of biopsy and showed rather high hematologic and renal response rates after treatment regimen based on bortezomib or thalidomide (62.5% and 75.0% respectively). Conclusions MM patients featured nephrotic syndrome, mild to moderate renal dysfunction, longer duration of renal damage, lower urine light chain levels or less percentage of bone marrow plama cell are prone to have amyloidosis,and the renal biopsy is indicated.The MM-MCN patients with deteriorated renal function would benefit from chemotherapy based on bortezomib or thalidomide.

Key words: Multiple myeloma, Myeloma cast nephropathy, Light chain amyloidosis, Renal biopsy