Multiple myeloma is a cancer originating in plasma cells, a type of white blood cell. These plasma cells are found within the bone marrow, the soft tissue inside bones that produces blood cells. Healthy plasma cells produce antibodies crucial for fighting infections. With multiple myeloma, these cells become abnormal, multiplying uncontrollably and accumulating in the bone marrow. This proliferation interferes with normal blood cell production and produces abnormal proteins, leading to various health complications.
Common Symptoms
Individuals with multiple myeloma often experience vague symptoms that overlap with other health conditions. Bone pain is frequently reported, commonly in the back, ribs, or hips, often worsening with activity. This pain results from damage cancerous plasma cells inflict on bone tissue.
Fatigue and weakness often stem from anemia, where abnormal plasma cells crowd out healthy blood-producing cells in the bone marrow, reducing red blood cell count. A compromised immune system, due to cancerous cells displacing normal white blood cells, can lead to frequent infections.
Kidney problems may manifest as changes in urination frequency, leg swelling, or nausea, from abnormal proteins damaging the kidneys. Elevated calcium levels (hypercalcemia) can also occur as bones break down, causing confusion, increased thirst, and constipation.
How Doctors Diagnose Multiple Myeloma
Diagnosing multiple myeloma involves specialized tests to detect abnormal plasma cells and their effects.
- Blood tests check for abnormal proteins like monoclonal protein (M-protein) and beta-2 microglobulin, produced by myeloma cells. These tests also assess kidney function, calcium levels, and complete blood counts to identify anemia or other blood cell abnormalities.
- Urine tests detect M-proteins, specifically Bence Jones proteins, indicating myeloma and potential kidney involvement.
- A bone marrow biopsy and aspiration are performed, typically from the hip bone, to examine the bone marrow. This procedure collects solid tissue and liquid samples to analyze plasma cell percentage and characteristics, including genetic makeup.
- Imaging studies visualize bone damage and tumor locations. While X-rays show “punched-out” or “lytic lesions,” more sensitive techniques like CT, MRI, and PET scans provide detailed views of bone lesions, bone marrow infiltration, and soft tissue involvement.
Appearance of Affected Areas
Multiple myeloma distinctly impacts bones and bone marrow. In bones, the disease manifests as osteolytic lesions, appearing as areas of bone destruction. These lesions can be seen on imaging as small holes or “moth-eaten” areas, particularly in the spine, ribs, skull, pelvis, and long bones. Cancerous plasma cells disrupt bone remodeling, accelerating breakdown while inhibiting new bone formation, leading to fragile bones prone to fractures.
Within the bone marrow, cancerous plasma cells accumulate and multiply, crowding out healthy blood-forming cells. This infiltration is observed during a bone marrow biopsy, where an increased percentage of abnormal plasma cells, often exceeding 10%, confirms the disease. This displacement affects red blood cell, white blood cell, and platelet production, contributing to anemia and weakened immunity.
The kidneys can also show signs of damage due to abnormal proteins produced by myeloma cells. These proteins, particularly free light chains, can form casts that block the kidney’s filtering tubules, leading to kidney dysfunction or failure. Under a microscope, kidney biopsies might reveal these protein casts and inflammation within the kidney tissue.
Distinguishing Multiple Myeloma
Multiple myeloma symptoms are often non-specific, resembling those of many other common health conditions. Bone pain, for example, might be mistaken for arthritis, osteoporosis, or general back pain. Fatigue and weakness are prevalent in various disorders, including anemia from other causes, or chronic conditions like diabetes. Kidney problems can also mimic other forms of kidney disease.
Due to this overlap in symptoms, a definitive diagnosis requires comprehensive medical evaluation. Relying solely on self-assessment can be misleading, as early symptoms are often subtle. Medical professionals use specialized tests to accurately identify the disease and ensure timely intervention.