Multiple myeloma, also known as cytomelanoma, is caused by the malignant transformation of plasma cells that synthesize and secrete immunoglobulins and the proliferation of a large number of malignant monoclonal plasma cells. The incidence of multiple myeloma varies around the world and is increasing in China. The age of onset is more than 40 years old, and those aged 50-70 years account for 75% of the total number of cases, and the ratio of men to women is 3:1. The cause of the disease is still unclear. (1) Skeletal pain: It is the main symptom of myeloma, and 60% of cases are the first symptom, the location is most common in the spine of the lower back, followed by the thoracic ribs, the initial intermittent pain gradually becomes persistent and severe, and the pain increases with activity. (2) Bone masses: Most of them are found in flat bones, especially in the sternum, ribs, skull, clavicle and mandible, etc. Local bones are elevated, hard to touch or rubber-like soft and tough, with elasticity or sound when pressed, and local pressure pain. The tumor tissue often infiltrates the nearby soft tissues, and bead-like changes in the sternum, ribs and jawbone joints are seen in half of the patients. (3) Infection: The lungs, urinary tract, skin, sinuses and blood of myeloma patients are more susceptible to infection, and infection often recurs during the course of the disease, especially in the late stage of the disease or during chemotherapy. (4) Anemia and cachexia: Due to the destruction of the bone marrow hematopoietic system, almost all patients have varying degrees of anemia and soon develop cachexia, and bleeding is due to thrombocytopenia, vascular damage and coagulation disorders. The manifestations are mainly skin purpura and mucosal oozing blood, with intracranial hemorrhage in the late stage. (5) Renal impairment: This is a characteristic feature of the disease, often occurring at the onset of the disease, 20% of renal failure occurs, uremia is the common cause of death. (6) Immunoglobulin abnormalities: The large amount of monoclonal immunoglobulin causes increased blood viscosity, especially blood flow slowdown and microcirculatory disorders, called hyperviscosity syndrome, patients can see capillary oozing or bleeding, limb numbness, brain dysfunction. (7) Neurological system: Infiltration and compression of nerves by tumor tissue and compression of spinal cord by pathological fracture of thoracic and lumbar vertebrae can lead to corresponding symptoms and signs. Such as paraplegia, urinary retention, neuralgia, limb numbness and movement disorders. (8) Other: such as hypercalcemia.