Myeloma vs. bone metastasis: How oncologists tell the difference
Fact-checked by While myeloma and bone metastases — areas of secondary bone cancer that have spread from somewhere else — both weaken and damage bones, their clinical management and outlook differ.
Myeloma is a blood cancer that initially forms from immune cells that reside in the bone marrow, the spongy center of bones where most blood cells are produced. In contrast, bone metastases are areas of cancer in the bone that have spread from a primary tumor elsewhere in the body. While nearly any cancer can spread to bones, some common ones are breast, lung, and prostate cancers.
Because these two conditions share similar symptoms, each one is an important part of the differential diagnosis for the other. Oncologists carefully evaluate collective findings from imaging scans, blood tests, and bone marrow biopsies to ensure an accurate diagnosis and develop an appropriate treatment plan.
Why myeloma and bone metastases can look similar
Both myeloma and bone metastases weaken and damage bones, leading to areas of bone destruction known as lytic lesions. Consequently, they can cause similar symptoms, including:
- bone pain
- frequent fractures
- high blood calcium levels from bone breakdown, which can cause confusion, weakness, nausea or vomiting, excessive thirst, and frequent urination
- spinal cord compression, a medical emergency leading to symptoms such as muscle weakness and loss of bladder or bowel control
Both conditions commonly affect the bones of the spine, pelvis, and ribs.
These similarities can make it difficult to distinguish between the two conditions, especially if a patient’s primary cancer has not yet been diagnosed before secondary bone metastasis occurs. Other rare forms of primary bone cancer that originate directly in bone tissue can also produce similar symptoms.
How to tell myeloma and bone metastases apart
Differentiating myeloma vs. bone metastasis may require multiple tests. While bone-related symptoms can appear identical in the two conditions, other symptoms differ substantially between them.
People with myeloma may experience symptoms like frequent infections, weakness, shortness of breath, and easy bruising or bleeding. Individuals with bone metastases often show symptoms tied directly to their primary cancer. For example, a patient with underlying lung cancer might experience a persistent cough or chest pain.
Oncologists rely on a number of diagnostic tests to help tell the difference between myeloma and bone metastases:
- Blood tests: identify unique hallmarks of myeloma, such as altered blood cell counts and M protein, an abnormal antibody produced by cancerous myeloma cells
- Bone scans and other imaging tests: detect the distinct patterns of bone damage associated with each condition
- Biopsies: definitively identify whether myeloma cells or other types of cancer cells are present in the tissue
Standard bone scans are specialized imaging tests that use a radioactive tracer to find bone disease. However, these scans often miss the specific type of bone damage caused by myeloma, but may be able to pick up on signs of bone metastases.
Other imaging tests, including CT, MRI, and PET scans, can distinguish myeloma vs. metastasis bone lesions. Lytic lesions in myeloma usually show up on these scans as multiple, relatively uniform areas of bone destruction. Bone metastases often exhibit more variable, irregular types of damage. These advanced imaging tests can also pinpoint the primary tumor location where the bone metastases originally spread from.
When other test results remain unclear, a bone marrow biopsy provides the most definitive way to diagnose myeloma. This procedure involves collecting a sample of the affected tissue and analyzing it in a laboratory to confirm the exact type of cancer cells present.
Each of these tests may play a role in how oncologists tell the difference between these conditions to establish the appropriate treatment plan.
Questions to ask an oncologist
When going through the testing process to identify myeloma, bone metastasis, or another type of bone cancer, a few things to ask an oncologist include:
- Based on my symptoms, what are some possible diagnoses?
- Do my blood tests show typical signs of myeloma, such as M protein?
- What additional diagnostic tests do you recommend next?
- What are some red flag symptoms I should be on the lookout for?
- What is the timeline for establishing my diagnosis and starting treatment?
- How might these different possible diagnoses affect treatment and outlook?
Rare Cancer News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
