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.
Multiple myeloma is characterized by excessive growth and malformation of plasma cells in bone marrow. The growth of these extra cells interferes with the production of red blood cells, white blood cells, and platelets, resulting in anemia, susceptibility to infection, and increased tendency toward bleeding. As the cancer cells grow and expand, pain and destruction of bone occurs.
Signs and symptoms
The earliest symptom of multiple myeloma is usually back pain. This disease should be considered in diagnosis or treatment of elderly patients with new onset of lower back pain. Arthritic symptoms may also occur: achiness, joint swelling, and tenderness, possibly from vertebral compression. Other effects include fever, malaise, slight evidence of peripheral neuropathy (such as peripheral paresthesia), pathologic fractures, and easy bruising.
As multiple myeloma progresses, symptoms of vertebral compression may become acute, accompanied by anemia, weight loss, thoracic deformities (ballooning), and loss of body height—5? (12.7 cm) or more—due to vertebral collapse.
Renal complications such as pyelonephritis (caused by tubular damage from large amounts of Bence Jones protein, hypercalcemia, and hyperuricemia) may occur. (See Bence Jones protein.) Severe, recurrent infection, such as pneumonia, may follow damage to nerves associated with respiratory function.