Bone tumors may be cancerous (malignant) or noncancerous (benign).
Cancerous tumors may start in the bone (primary cancer) or start in other organs (such as the breast or prostate) and spread to the bone (metastatic cancer).
Tumors may cause unexplained, progressively worsening bone pain, swelling, or a tendency to fracture easily.
The diagnosis is sometimes based on the results of an imaging test (such as x-ray, computed tomography, or magnetic resonance imaging) but often requires removing a tissue sample of the tumor or bone for examination under a microscope (biopsy).
Bone tumors may be noncancerous or cancerous and primary or metastatic.
Primary bone tumors originally start in the bone. Primary bone tumors Primary Cancerous Bone Tumors Tumors that originally start in the bone are called primary bone tumors. Primary bone tumors may be noncancerous (benign) or cancerous (malignant). After cancer is diagnosed, it is staged. Staging... read more 
may be noncancerous or cancerous.
Metastatic bone tumors are cancers that spread to (metastasize) the bone from other areas in the body (for example, from the breast or prostate gland—see also Development and Spread of Cancer Spread Malignant transformation is the complex process by which cancerous cells develop from healthy cells. It consists of several steps: Initiation Promotion Spread (See also Overview of Cancer.) read more ). Metastatic bone tumors Metastatic Bone Tumors Cancers that begin elsewhere in the body may spread (metastasize) to the bones. In particular, cancers of the breast, lung, prostate gland, kidney, thyroid gland, and colon may metastasize to... read more are always cancerous.
In children, most bone tumors are primary and noncancerous. Some bone tumors (such as osteosarcoma Osteosarcomas (osteogenic sarcoma) Tumors that originally start in the bone are called primary bone tumors. Primary bone tumors may be noncancerous (benign) or cancerous (malignant). After cancer is diagnosed, it is staged. Staging... read more and Ewing sarcoma Ewing sarcoma of bone Tumors that originally start in the bone are called primary bone tumors. Primary bone tumors may be noncancerous (benign) or cancerous (malignant). After cancer is diagnosed, it is staged. Staging... read more ) are primary and cancerous. Very few are metastatic (such as neuroblastoma Neuroblastoma Neuroblastoma is a common childhood cancer that grows in parts of the nervous system or adrenal glands. What causes neuroblastoma is often not known. Symptoms depend on where neuroblastomas... read more and Wilms tumor Wilms Tumor Wilms tumor is a specific kind of kidney cancer that occurs mainly in young children. The cause of Wilms tumor is not known, but some children may have a genetic abnormality that increases their... read more ).
In adults, most cancerous bone tumors are metastatic. Overall, noncancerous bone tumors are relatively common, but cancerous primary bone tumors are rare, occurring in only about 3,900 people yearly in the United States. This number does not include multiple myeloma Multiple myeloma Tumors that originally start in the bone are called primary bone tumors. Primary bone tumors may be noncancerous (benign) or cancerous (malignant). After cancer is diagnosed, it is staged. Staging... read more , a cancer that develops in the marrow inside the bone rather than in the hard bone tissue that makes up the bone.
Although benign bone tumors do not metastasize, some types grow rapidly and destroy nearby tissues.
Multiple myeloma
Multiple myeloma (see also Plasma Cell Disorders: Multiple Myeloma Multiple Myeloma Multiple myeloma is a cancer of plasma cells in which abnormal plasma cells multiply uncontrollably in the bone marrow and occasionally in other parts of the body. People often have bone pain... read more ) occurs mostly in older adults and involves the bone marrow (the blood-forming tissue inside the cavity of the bone) rather than the hard tissue that makes up the bone. Thus, it is usually considered a cancer of the bone marrow rather than the bone itself (unlike primary cancerous bone tumors Primary Cancerous Bone Tumors Tumors that originally start in the bone are called primary bone tumors. Primary bone tumors may be noncancerous (benign) or cancerous (malignant). After cancer is diagnosed, it is staged. Staging... read more ). It is more common than cancers of the hard tissue that makes up bone.
Symptoms of Bone Tumors
A person may sometimes have a painless lump, which may eventually become painful, but often the first symptom of a bone tumor is bone pain. The pain can be severe. Pain may occur when bearing weight or when at rest (particularly at night) and tends to progressively worsen. Sometimes a tumor, especially if it is cancerous, gradually weakens a bone. The weakness makes it much easier for the bone to break (fracture) while doing routine activities (this type of fracture is called a pathologic fracture).
Diagnosis of Bone Tumors
X-rays
Often magnetic resonance imaging (MRI) and sometimes computed tomography (CT) or positron emission tomography with CT (PET-CT)
Sometimes bone scan
Biopsy
When people have a joint or limb that is always painful, even when they are not using it, doctors typically do x-rays X-rays A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more 
. X-rays can show doctors that the bone has an abnormal appearance or can show a growth or a hole in the bone. Although doctors can see such abnormalities on x-rays, they usually cannot tell whether a tumor is noncancerous or cancerous. However, some tumors can be identified as noncancerous by an x-ray. For example, this identification is often possible with Paget disease of bone Paget Disease of Bone Paget disease of bone is a chronic disorder of the skeleton in which areas of bone undergo abnormal turnover, resulting in areas of enlarged and softened bone. The breakdown and formation of... read more 
, enchondromas Enchondromas Noncancerous bone tumors are benign, which means they are not cancer and in general never or rarely spread to other areas of the body. However, they can cause problems because they may weaken... read more 
, bone cysts Bone Cysts Many noncancerous (benign) bone abnormalities may resemble bone tumors but are not. (See also Overview of Bone Tumors.) Aneurysmal bone cysts usually develop before people reach age 25, and... read more 
, nonossifying fibromas Nonossifying fibroma (fibrous cortical defect, fibroxanthoma) Noncancerous bone tumors are benign, which means they are not cancer and in general never or rarely spread to other areas of the body. However, they can cause problems because they may weaken... read more , and fibrous dysplasia Fibrous dysplasia Noncancerous bone tumors are benign, which means they are not cancer and in general never or rarely spread to other areas of the body. However, they can cause problems because they may weaken... read more .
If an x-ray does not give doctors enough information, computed tomography Computed tomography (CT) and magnetic resonance imaging (MRI) A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more (CT) and magnetic resonance imaging Computed tomography (CT) and magnetic resonance imaging (MRI) A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more (MRI) often help them determine the exact location and size of the tumor and give additional information about the nature of the tumor. However, these tests usually do not provide a specific diagnosis.
Doctors may do bone scans Bone scanning A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more to identify the locations of many tumors at one time because bone scans show the entire skeleton.
Doctors may also do positron emission tomography Positron Emission Tomography (PET) Positron emission tomography (PET) is a type of medical imaging called radionuclide scanning. By detecting radiation after a radioactive material is administered, PET creates images that can... read more 
(PET or PET scan) , usually as PET combined with CT scanning (PET-CT PET computed tomography (PET-CT) Positron emission tomography (PET) is a type of medical imaging called radionuclide scanning. By detecting radiation after a radioactive material is administered, PET creates images that can... read more ). PET and PET-CT are other types of imaging tests that can show where a cancer is, where it has spread, and how it is responding to treatment.
If cancer is a reasonable possibility, a biopsy is usually necessary for diagnosis. Three types of biopsies may be done depending on the tumor:
Aspiration biopsy
Core biopsy
Open biopsy
Many tumors can be biopsied.
In an aspiration biopsy, doctors insert a needle into the tumor and withdraw some cells. No incision is needed. However, because the needle used is very small, sometimes normal cells may be sampled and cancer cells are missed, even when cancer cells are lying right beside the normal cells.
A core biopsy is done with a larger needle and often done so that more cells can be withdrawn and examined. Because both aspiration and core biopsies are done by using needles, they are considered needle biopsies. Needle biopsies are often done with ultrasound guidance or radiographic imaging (fluoroscopy or CT) to increase accuracy.
An open biopsy is a surgical procedure. Sometimes an open biopsy is done when more tissue is needed for the doctor to make an adequate diagnosis. In this procedure, a surgeon cuts through the skin and into the deeper tissues to obtain an adequate sample for diagnosis. This procedure can sometimes be done at the same time that surgery is done to treat the tumor. If a portion of the tumor is removed, the procedure is called an incisional biopsy; if the entire tumor is removed, it is called an excisional biopsy.
More Information
The American Cancer Society: Cancer Facts & Figures 2022
