Lytic lesions refer to areas of bone destruction that result in holes. They typically occur due to a disease, such as cancer. In some cases, they may result in painful fractures that can be disabling and require surgery to reinforce and stabilize the bone.

Some people may also refer to lytic lesions as bone or osteolytic lesions. The term refers to spots of bone damage that can occur with conditions that affect bone. For example, evidence notes that up to 90% of people with multiple myeloma will develop lytic lesions during the course of the disease.

Multiple myeloma is a bone marrow cancer that affects a person’s plasma cells. These are a type of white blood cell that fights infection that the body produces in the bone marrow.

A doctor may describe multiple myeloma as a type of plasma cell neoplasm. This term can refer to abnormal plasma cells forming tumors in bones. When this occurs, it can make bones thin and create areas of weaker bones, or lytic lesions, that are vulnerable to fractures. Bone pain and bones that break easily are common symptoms of multiple myeloma.

In this article, we will discuss lytic lesions and how they relate to multiple myeloma.

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A lytic lesion describes an area of bone damage that often appears as a hole. These lesions can develop in any section of the bone and often occur due to cells in the bone that start to divide and multiply uncontrollably. This can result in a lump or mass of atypical tissue that can destroy healthy tissue and weaken the bone.

Most bone lesions are benign, or not life threatening, and will not spread to other parts of the body. However, others can be malignant, meaning they are cancerous. These bone lesions also sometimes metastasize, which is when the cancer cells spread to other parts of the body.

These lesions result in holes that can make bones more likely to break under minor pressure or injury. The bones that lytic lesions commonly affect include the spine, pelvis, ribs, skull, and the long bones of the arms and legs. Bone disease is a hallmark feature of multiple myeloma — research suggests that up to 80% of people with multiple myeloma have lytic lesions at the time of diagnosis.

A person’s bone tissue is capable of regenerating. Old bone tissue breaks down, and new bone tissue replaces it. The body is able to carefully balance this process, known as remodeling, to help maintain the health of the skeleton. Conditions, such as multiple myeloma, may disrupt this balance, which can cause the bone to become weaker in certain areas, resulting in lytic lesions.

Two kinds of bone cells work together to keep bones healthy: osteoclasts and osteoblasts. Osteoclasts are cells in the body that play a role in breaking down old bone tissue. Osteoblasts then play a role in the formation of new bone tissue.

Multiple myeloma can upset the balance of this process. Multiple myeloma cells produce osteoclast-activating factors. These factors signal the osteoclast cells to break down bone uncontrollably. Multiple myeloma cells also inhibit the formation of osteoblast cells, preventing bone repair.

These two factors combine, resulting in too much bone breakdown and insufficient bone buildup. This can then cause bones to weaken and allow lytic lesions to form.

A majority of people with multiple myeloma will develop a fracture during the course of the disease. This is because lytic lesions weaken bones, making them more prone to breaks. A person with lytic lesions may also experience bone pain.

As lytic lesions form, an individual’s bones break down quickly. During this process, large amounts of calcium enter the bloodstream. Hypercalcemia is a term that refers to high levels of calcium in the blood.

If a person has hypercalcemia, they may experience symptoms, such as:

  • kidney problems
  • dehydration and extreme thirst
  • urinating more often
  • fatigue
  • constipation
  • confusion
  • abdominal pain
  • loss of appetite

Medical professionals will often use imaging tests to help diagnose and monitor bone diseases, such as lytic lesions, in multiple myeloma. This will typically involve X-rays but may also include CT and MRI scans. These scans allow health experts to take images of the bone to help them determine if lytic lesions are present.

As bone disease is a prominent feature of multiple myeloma, it highlights the important role of imaging in diagnosis.

Typically, the most effective treatment for lytic lesions involves treatment of the underlying condition and supportive treatment for the bone. For example, common treatments for multiple myeloma may include:

  • Chemotherapy: This treatment involves the use of certain drugs to kill rapidly dividing cancer cells. Chemotherapy can prevent these cells from growing and making more cancer cells.
  • Stem cell therapy: During this procedure, a person receives a dose of chemotherapy to kill the cells in their bone marrow. This process also kills the cancer cells. The person then receives stem cells, which can produce new, healthy blood-forming cells.
  • Medications: A doctor may prescribe certain medications to treat multiple myeloma. These can include corticosteroids, biologic therapies, and targeted therapies.

A doctor may also recommend bone-modifying agents (BMAs) to prevent further bone damage and help correct or prevent hypercalcemia. Examples of BMAs available to treat multiple myeloma include:

A person may also require surgery to help strengthen bones. This may involve the insertion of rods or plates into fragile bones to provide additional support.

Lytic lesions describe areas of bone damage that typically occur due to rapidly dividing cells in the bone. Multiple myeloma is a cancer of the plasma cells and a common cause of lytic lesions.

Bones within a healthy skeleton undergo a process known as remodeling that allows them to regenerate. Multiple myeloma can disrupt the balance of this process. This can result in an increased rate of bone destruction that causes lytic lesions to form.

In addition to treating the underlying cause of the lesions, a person may also require other treatments to reinforce and stabilize their bones to prevent fractures.