A bone tumor is when bone cells divide in an unusual and abnormal way and can form a mass. This mass is called a tumor. Bone tumors form in the bones. As the tumor grows, the abnormal tissue can displace healthy tissue. Tumors can be benign or malignant.

Benign tumors are not cancerous. Although benign bone tumors usually stay in place and are not likely to be fatal, they are still abnormal cells and may require treatment. Benign tumors can grow and could compress your healthy bone tissue and cause future problems.

Malignant tumors are cancerous. Malignant bone tumors can cause cancer to spread throughout the body.

Primary bone cancers

Les quatre types les plus courants de cancer osseux primaire sont les suivants :

Multiple myeloma

Multiple myeloma is the most common primary bone cancer. It is a malignant tumor of the bone marrow – the soft tissue in the center of many bones that produces blood cells.

Osteosarcoma

Osteosarcoma is the second most common primary bone cancer. Osteosarcoma is a mesenchymal neoplasm that produces osteoid and woven bone matrix. The production of osteoid matrix is the “sina qua non” for diagnosis. [The amount of matrix can vary from well-formed trabeculae (indicative of a benign process), dense osteoid (seen in the sclerotic variant of osteoblastic OGS) to discrete amounts of the matrix (seen in the fibroblastic or small cell variant of osteogenic sarcoma).

Ewing’s sarcoma

Ewing’s sarcoma is the second most common primary malignant bone tumor. It primarily affects adolescents in the second decade of life and is a highly metastatic class of sarcoma. Despite the use of radiation therapy or surgery, it is estimated that historically 85% to 90% of patients have died within months due to metastasis. With significant advances in the treatment of the disease with both local therapy and adjuvant multi-agent chemotherapy, the 5-year survival rate has improved from less than 20% to more than 70%, but the recurrence rate remains high.

Chondrosarcoma

Le chondrosarcome est une tumeur maligne composée de cellules productrices de cartilage.

Benign bone tumors

There are many types of benign bone tumors, as well as some diseases and conditions that resemble bone tumors. Although these conditions are not really bone tumors, in many cases they require the same treatment.

Common types of benign bone tumors – and conditions that are usually grouped with tumors – include the following:

  • Non-ossifying fibroma
  • Unicameral bone cyst (simple)
  • Osteochondroma
  • Giant cell tumor
  • Enchondroma
  • Fibrous dysplasia
  • Chondroblastoma
  • Aneurysmal bone cyst
  • Osteoid osteoma

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Causes of bone tumors

In most cases, it is not known why a person develops bone cancer.

You are more likely to develop it if you :

  • Exposure to radiation during radiation therapy
  • Have Paget’s disease of the bone
  • Have a rare genetic disorder called Li-Fraumeni syndrome

Symptoms of bone tumors

  • Bone pain that persists, worsens over time and lasts through the night
  • Swelling and redness (inflammation) on a bone, which can make it difficult to move if the affected bone is near a joint
  • A visible bump on a bone
  • A weak bone that breaks (fractures) more easily than normal
  • Problems moving – for example, walking with a limp.

However, the vast majority of malignant tumors are actually formed by metastasis from other sites, the most prevalent source being the breast in women and the prostate in men.

How does the bone react to the tumor?

  • Bone reacts in two ways
    • either by removing part of itself
    • or by creating more of himself
  • If the tumor is growing rapidly, it will be forced to withdraw (defense)
  • If the tumor grows slowly, the bone may have time to attack and try to form a sclera around the lesion.

Periosteal reaction

  • A periosteal reaction occurs whenever the periosteum is irritated.
  • It can happen due to a malignant tumor, benign tumor, infection or trauma
  • There are two types:
    • Benign
      • Solid
    • Malign
      • Onion or laminated peel
      • Sunburst
      • Codman triangle

Identification of a tumor on x-ray

  • Place where the lesion is located:
    • epiphysis
    • metaphysis
    • diaphysis
  • Margin of lesion:
    • Well defined with surrounding area of ​​reactive sclerosis in benign lesions.
    • Poorly defined in malignant lesions.
  • The bone destruction model:
    • Geographical
      • seen in slow growing tumors where there is a narrow transition zone between normal and abnormal bone as in most benign lesions
    • Moth eaten
      • Several lytic areas scattered throughout the bone, as in Ewig’s sarcoma
    • Permeation
      • Present in poorly demarcated lesions with a large transition zone, such as high-grade Ewig’s sarcoma and chondrosarcoma.
  • Type of periosteal reaction
    • Solid: cortical thickening as in osteoid osteoma
    • Laminate: as in Ewing’s sarcoma (onion peel)
    • Complex: as in osteosarcoma (Sunburst model)

Bone destruction model

Geographic bone destruction

The geographic bone destruction pattern is the least aggressive, and usually indicates a slow-growing lesion. The periphery may be smooth or irregular, but in either case it is well defined and easily differentiated from the surrounding bone by a brief transition zone. Sometimes, a sclerotic periphery of variable size surrounds the lesion. The thicker and more complete the sclerotic margin, the less aggressive the process. Benign bone tumors usually demonstrate geographic bone destruction of the bone.

Moth-eaten bone destruction.

The moth-eaten pattern of bone destruction is more aggressive and is characterized by a lesion that develops more rapidly than one that is geographic. This pattern is associated with a less defined or demarcated periphery and with a more extensive transition zone between normal and abnormal bone. Malignant bone tumors and osteomyelitis may demonstrate “moth-like” bone destruction.

Permeative bone destruction

The permeative model denotes an aggressive bone lesion with the potential for rapid growth. The lesion is poorly demarcated and may merge imperceptibly with uninvolved bony sections and create a very long transition zone. Its actual size is larger than what can be seen on x-rays. Some malignant bone tumors, such as Ewing’s sarcoma, may present with patent bone destruction. Rapidly progressive osteomyelitis and osteoporosis, however, may reveal permeable bone destruction.

Non-aggressive lesion, solid periosteal reaction

A tumor that grows slowly, such as osseoid osteoma (radiolucent nidus), induces periosteal cells to deposit bone in a continuous manner.

Kayser classification showing the location of osteoid osteomas in tubular bones. The nidus is shown in white. Black areas show new bone formation, sclerosis, cortical thickening and edema.

Type of periosteal reaction

Aggressive, laminated or onion skin lesion

An irregularly growing tumor that grows in spurts and stops. produces a characteristic lamellar or onion skin appearance. When the lesion grows rapidly, the periosteal cells do not have enough time to lay down bone.
The multilayer periosteal reaction, also known as the lamellar periosteal reaction or onion skin, shows several concentric parallel layers of new bone adjacent to the cortex, reminiscent of the layers of an onion. The layers are said to be the result of periods of variable growth 2 and would indicate a pathological process of intermediate aggressiveness. Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org. From the case rID: 7844

Very aggressive lesion, Sunburst

A very rapidly growing lesion pushes periosteal cells outward as the lesion expands, with each periosteal cell leaving a bone formation that resembles a hair on the head or a sun.
Osteogenic sarcoma A poorly defined sclerotic area affecting the metaphysis of the distal fibula with an aggressive periosteal reaction (sunburst type). This lesion concerns the adjacent posterior surface of the tibia and the calcaneus below. It is associated with moderately severe soft tissue swelling.Case courtesy of Dr Aditya Shetty, Radiopaedia.org. From the case rID: 27260

Very very aggressive lesion, Codman triangle

  • Too rapid growth for the periosteum
  • The periosteum responds only to the edges of the raised periosteum which will ossify at a small angle to the bone surface

Osteoid osteoma

Ewing’s sarcoma

Lodwick classification of lytic bone lesions

  • Type 1: Geographic osteolysis: The margins have a thin transition zone and may be sclerotic or well defined.
    • IA: Thin sclerotic margins. Almost always non-aggressive.
    • 1B: Well-defined margins. Generally non-aggressive.
    • 1C: Any part of the margin is indistinct. Agressive.
  • Type 2: Mitigated osteolysis: It is difficult to define any border. Aggressive.
  • Type 3: Permeative osteolysis: The permeative model is characterized by multiple small holes that infiltrate the bone.