If you have multiple myeloma, cancerous plasma cells divide and grow inside your bone marrow. Plasma cells are white blood cells that make antibodies. They're part of your immune system. In multiple myeloma, plasma cells that don't work to fight foreign invaders in your body replicate and crowd out normal plasma cells and other cells in your bone marrow.
What are Lytic Lesions?
Also known as bone lesions or osteolytic lesions, lytic lesions are spots of bone damage that result from cancerous plasma cells building up in your bone marrow. Your bones can't break down and regrow (your doctor may call this remodel) as they should. This makes them thin and creates areas of weaker bones that are vulnerable to fractures. Almost everyone who has multiple myeloma will have bone lesions at some time.
In normal bone, the process of bone remodeling keeps your bones healthy and strong. Special cells called osteoclasts break down old bone. Osteoblasts lay down new bone in its place.
With myeloma, the cancerous plasma cells (called myeloma cells) make chemicals called osteoclast activating factors (OAFs). These OAFs tell the osteoclasts to break down bone faster than usual, so old bone is broken down faster than new bone is made.
This causes bone lesions, and they can make your bones weak and break more easily.
Multiple myeloma isn't the only form of cancer that can affect your bones. Other types that can cause bone lesions include:
- Breast cancer
- Kidney cancer
- Lung cancer
- Prostate cancer
- Thyroid cancer
Signs that multiple myeloma is affecting your bones include:
- Pain. Bone pain is a common symptom. You usually feel it when you move but not when you're still.
- Where does it hurt? You may feel pain in your
- Fractures. About 80% of people with myeloma will have a broken bone caused by myeloma. This is called a pathologic fracture. About 1 out of every 3 people with myeloma learn they have the disease when a bone breaks.
The spine is the most common place for a fracture, but it can happen in other bones as well. Bones that make up the spine -- called vertebrae -- can become so weak they collapse. These are compression fractures.
These fractures are painful and can cause a hunched posture and a loss of height. They also can make it hard for you to move. Because your spine is shortened, you don't have as much space in your chest and abdomen. This can make it harder for you to breathe and eat.
With some compression fractures, the nerves between the vertebrae can be pressed or pinched. This sometimes causes pain, numbness, and weakness in the legs.
- Hypercalcemia. When your bones break down quickly, a lot of calcium gets released into your blood. A high calcium blood level is called hypercalcemia. It can cause an upset stomach, vomiting, and constipation. All that extra calcium can sometimes lead to kidney stones. Hypercalcemia can make you less hungry and thirstier and make you restless and confused.
- Limping. If a bone with a tumor breaks, it can make you limp. This is more likely in the later stages of the disease.
- Low blood cell counts. As myeloma cells crowd out your regular blood cells in the bone marrow, you could get conditions like:
- Anemia. If you have too few red blood cells, you can feel weak, short of breath, and dizzy and have a hard time exercising.
- Leukopenia. When you don't have enough white blood cells, you may be more likely to get infections like pneumonia.
- Thrombocytopenia. When platelet counts are low, you might bleed a lot from a simple cut or scrape.
Nervous System Problems
Myeloma can lead to a number of problems with your nerves, including:
- Spinal compression. If myeloma affects the bones in your spine, they can press down on your spinal cord. You might feel:
- Sudden, severe back pain
- Numbness or weakness, often in your legs
- Muscle weakness, often in your legs
If you feel something like this, get medical help right away. This is a medical emergency and can result in permanent paralysis.
- Nerve damage. Bone lesions can sometimes press on nerves and cause pain. Myeloma proteins can be toxic to your nerves. This can lead to a condition called peripheral neuropathy that causes a pins and needles feeling, often in your legs and feet.
Get medical help right away if you have any of these symptoms.
Diagnosis and Tests
Blood tests and X-rays can show a high probability of someone having multiple myeloma. But confirmation of the diagnosis requires a bone marrow biopsy to get tissue. A biopsy is the most common test used to diagnose lesions on your bones. Your doctor will remove a piece of tissue or take a sample of cells from your body and check it in a lab under a microscope for signs of cancer. These types of biopsies are most often used to help diagnose multiple myeloma:
- Bone marrow biopsy. The doctor will numb the top of your rear hip bone and remove a splinter of bone marrow tissue. They'll look at the size and shape of the cells, how they're arranged, how many there are to see if myeloma cells are present.
- Bone marrow aspiration. The doctor will numb the top of your rear hipbone and use a needle to take a sample of liquid bone marrow. They may order other tests on the aspirated liquid, such as:
- Immunohistochemistry. This test treats cells from the biopsy with a special protein so they'll change color. This helps identify myeloma cells.
- Flow cytometry. This test treats the bone marrow sample with proteins that stick only to certain cells. It helps determine if the cells are abnormal, myeloma, another type of cancer, or a non-cancerous disease.
- Cytogenetic analysis (karyotyping). This test looks for changes to chromosomes in bone marrow cells and myeloma cells. Changes in your DNA can give doctors an idea of how aggressive your myeloma is.
- Fluorescence in situ hybridization (FISH). Doctors use special dyes to attach to your chromosomes and spotlight changes too small for other tests to find.
Treatment of Pain
- Medications are one way to help you handle pain, and there are many to choose from. Your doctor will talk with you about when and how often to take pain medicine. Always ask your doctor before you take anything, even those you can get from the drugstore. Drugs that treat multiple myeloma pain include:
- Over-the-counter pain relievers, like acetaminophen, aspirin, ibuprofen, and naproxen. They help with mild to moderate pain.
- Opioids. These are stronger pain-fighting medicines that you get with a doctor's prescription. Morphine is one of the most common for multiple myeloma pain. Other opioids include codeine, fentanyl, hydrocodone, hydromorphone, methadone, and oxycodone. These come in pills, patches, lozenges, sprays. If used for a long time, they can lead to dependence, so be sure to follow your doctor's instructions for taking them.
- Antidepressants. Some of these drugs, such as amitriptyline, duloxetine, and nortriptyline, can help treat nerve pain, called neuropathy, that often comes with multiple myeloma.
- Anticonvulsants. Medications like gabapentin (Neurontin), pregabalin (Lyrica), and topiramate (Topamax) also treat nerve pain.
- Corticosteroids. These medicines, like dexamethasone and prednisone, can help fight tumors and control inflammation.
- Anesthetics. Lidocaine skin patches, ointments, and gels can numb pain in specific areas. Your doctor can also inject anesthetic or anti-inflammatory drugs near a painful spot or nerve center, which is called a nerve block.
- Radiation. External beam radiation, which uses a machine to beam energy at the cancer, can be used to treat:
- Painful bone lesions that haven't responded to chemotherapy
- Spinal cord compression
- Surgery. Surgeons can insert rods and plates to support fragile bones.There are two treatments for fractured vertebrae that can stabilize the bone and help ease back pain:
- Percutaneous vertebroplasty. Your doctor injects the broken vertebrae with medical-grade cement.
- Balloon kyphoplasty. The doctor uses a tool called an inflatable bone tamp to create a space in the vertebra to inject medical-grade cement and shore up the bone.
- Intrathecal pump. This small device is inserted into your body and drips pain medicine into the area around your spinal cord.
- TENS. Short for transcutaneous electrical nerve stimulator, this device goes on your skin and releases low-voltage electricity to block nerve pain signals.