Two diagnoses from bone marrow biopsy: multiple myeloma and Paget's disease of bone.

Multiple myeloma and Paget's disease of bone show certain similarities such as increased osteoclastic activity and predilection to the axial skeleton. However, pathological and radiological changes of the bones are distinctive between multiple myeloma and Paget's disease of bone. This case report describes a patient who had a concomitant diagnosis of multiple myeloma and Paget's disease evidenced from bone marrow biopsy. Such a co-existence is rare, with only a few cases reported so far.