Multiple myeloma is also known as malignant plasmacytoma, plasma cell myeloma, and myelomatosis. It’s a disseminated neoplasm of marrow plasma cells that infiltrates bone to produce osteolytic lesions throughout the skeleton (flat bones, vertebrae, skull, pelvis, ribs); in late stages, it infiltrates the body organs (liver, spleen, lymph nodes, lungs, adrenal glands, kidneys, skin, GI tract). Multiple myeloma strikes mostly men older than age 40.

The prognosis is usually poor because the disease is commonly diagnosed after it has already infiltrated the vertebrae, pelvis, skull, ribs, clavicles, and sternum. By then, skeletal destruction is widespread and, without treatment, leads to vertebral collapse. Early diagnosis and treatment prolong the lives of many patients by 3 to 5 years. Death usually follows complications, such as infection, renal failure, hematologic disorders, fractures, hypercalcemia, hyperuricemia, or dehydration.