Background: Multiple myeloma (MM) extramedullary disease (EMD) is an invasive growth of-clonal plasma cells that, is characterized by myeloma cells escaping from the bone marrow microenvironment, entering the blood circulation and infiltrating and growing in other organs. Soft-tissue involvement was associated with significantly shorter progression-free survival and overall survival, with a poor prognosis and a median survival of 8.5 months. Among the sites involved in extramedullary lesions, the abdomen and back are rare. The prognosis of soft tissue masses located in extramedullary organs is the worst, and the treatment of soft tissue masses with enlargement of extramedullary lesions is still difficult because the poor effects of radio-chemotherapy. Case Presentation: We present an MM patient who experienced multiple skeletal-related events with EMD in the neck, chest, abdomen, and back after four surgical interventions, multiple cycles of chemotherapy and autologous peripheral blood stem cell transplantation, and surgical resection. Conclusions: MM with a large extramedullary plasma cell tumour often is not responsive to chemotherapy and radiotherapy. For continuously growing masses, surgical resection is recommended to reduce the tumour load, relieve pain, and relieve secondary vascular and nerve compression.