Plasma cell myeloma showing progressive bone destruction during long-term clinical remission

A case of plasma cell myeloma initially producing Bence Jones protein of lambda type was presented. BJ protein disappeared within two months of cyclophosphamide and betamethasone administration. A complete remission continued for the following 2 years and 8 months with no medication, although the patient insidiously developed osteolytic lesions. The discrepancy of long-term negative BJP and clinical remission without medication and progressive bone destruction was reported.