Myeloma (also known as plasma cell tumor) is a malignant tumor originating from plasma cells in the bone marrow. It is a common malignant tumor. It can be divided into single and multiple, with the latter being more common. Multiple myeloma, also known as cellular myeloma (Multiple myeloma, referred to as MM), is caused by the malignant transformation of plasma cells that synthesize and secrete immunoglobulins. The proliferation of a large number of monoclonal malignant plasma cells easily involves soft tissues. In the late stage, there may be extensive metastasis, but rarely lung metastasis. It is more common in the spine, accounting for 10% of primary spinal tumors, and is more common in the lumbar spine. The age of onset is mostly over 40 years old, and the ratio of men to women is about 2:1. It is more common in men over 40 years old, and the common sites are the spine, ribs, skull, sternum, etc.