Bone Cancer.....

What is bone cancer?

Normal bone tissue

Bone is the framework supporting your body. Most bones are hollow. The outer part of the bone is a network of fibrous tissue called matrix upon which calcium salts are established.

The hard outer bone layer is made of compact bone (cortical) covering the spongy (trabecular) bone lighter within. Outside the bone is covered with a layer of fibrous tissue called periosteum. Some bones are hollow and have a space called the medullary cavity containing the soft tissue called bone marrow (discussed below). The tissue lining the marrow cavity is called endosteum. At each end of the bone is an area of ​​a milder form of bone-like tissue called cartilage.

Cartilage is softer than bone, but firmer than most tissues. It is made of a matrix mixed with a fibrous tissue similar to a gel that does not contain a lot of calcium substance.

Most of the bones start out as cartilage. The body then put down on calcium cartilage to form bone. After bone forms, some cartilage may remain in the ends to act as a buffer between the bones. This cartilage, along with ligaments and other tissues connect bone to form a joint. In adults, the cartilage is mainly at the end of some bones, as part of a joint. It also looks at the place in the chest where the ribs meet the sternum (breastbone) and parts of the face. The trachea (windpipe), larynx (voice box), and the outer ear are other structures that contain cartilage.

Own bone is very hard and strong. Some bone is capable of supporting up to 12,000 pounds per square inch. It takes as much as 1,200 to 1,800 pounds of pressure to break the femur (thigh bone). Bone itself contains two types of cells. The osteoblast cell is established new bone, and osteoclasts dissolves cell is the old bone. Bone often seems as if it does not change much, but the truth is that is very active. Throughout our bodies, new bone is always forming while old bone is dissolving.

In some bone marrow is only fatty tissue. In other bone marrow is a mixture of fat cells and blood-forming cells. Forming cells produce red blood cells, white cells and platelets in the blood. Other cells include bone marrow plasma cells, fibroblasts and reticuloendothelial cells.

The cells of any of these tissues can become a cancer.

Types of bone tumors
Most of the time when people with cancer are told they have cancer in your bones, the doctor is talking about a cancer that has spread to the bone from elsewhere. This is known as metastatic cancer. It can be seen in many different advanced cancers, such as breast cancer, prostate cancer, and lung cancer. When these types of cancer in the bone are viewed under a microscope, they look like they came tissue. For example, if someone has lung cancer that has spread to bone cancer, cancer cells in the bone still look and act like cell lung cancer. They do not look or act like cells of bone cancer, although they are in the bones. Because these cancer cells still act as cell lung cancer, which still need to be treated with drugs used for lung cancer.

Other cancers that are sometimes called "bone cancers" start in the cells that form bone marrow blood - not in the bone itself. The most common cancer that originates from the bone marrow, causing bone tumors is called multiple myeloma. Another cancer that starts in the bone marrow is leukemia, but is generally considered a cancer of the blood instead of bone cancer. Sometimes lymphomas, most often originate in lymph nodes, they can begin in the bone marrow. Multiple myeloma, lymphoma, and leukemia are not discussed in this document. For more information on these cancers, refer to each individual document.

A primary bone tumor begins in the bone itself. True (or primary) bone cancers are called sarcomas. Sarcomas are cancers that start in the bones, muscles, fibrous tissue, blood vessels, fatty tissue and some other tissues. They can develop anywhere in the body.

There are several different types of bone tumors. Their names are based on the area of ​​bone or surrounding tissue that is affected and the type of cells that form the tumor. Some primary bone tumors are benign (noncancerous), and others are malignant (cancerous). Most bone cancers are sarcomas.

Benign bone tumors
Benign tumors do not spread to other tissues and organs, and usually are not life threatening. They are generally cured by surgery. Types of benign bone tumors include:

Osteoid osteoma (OS-tee-Oya OS-tee-oh-ma)
Osteoblastoma (OS-tee-oh-blas-TOE-muh)
Osteochondroma (OS-tee-oh-kon-droh-muh)
Enchondroma (en-kon-droh-muh)
Chondromyxoid (kon-dro-MIX-Oya) fibroma.

These benign tumors are discussed later in this document, which is limited to bone cancers.

Malignant bone tumors
Osteosarcoma: Osteosarcoma (also called osteogenic sarcoma) is the most common primary bone cancer. This type of cancer starts in bone cells. It most often occurs in young people between the ages of 10 and 30, but about 10% of osteosarcoma cases develop in people aged 60 to 70 years. It is uncommon in middle age and is more common in men than in women. These tumors develop most often in the bones of the arms, legs or pelvis. This type of cancer is not discussed in detail here, but is covered in our osteosarcoma document.

Chondrosarcoma: Chondrosarcoma (KON-droh-sar-KOH-muh) is a cancer of the cartilage cells. It is the second most common primary bone cancer. This cancer is rare in people under age 20. After age 20, the risk of getting a chondrosarcoma goes up until about 75 years women receive this type of cancer as often as men.

Chondrosarcomas can develop anywhere there cartilage. Most develop in bones such as the pelvis, leg bone or arm bone. Occasionally, chondrosarcoma will develop in the trachea, larynx and chest wall. Other sites are the scapula (shoulder blade), ribs or skull.

(Not cancerous), benign tumors of cartilage are more common than malignant. These are called enchondromas. Another type of benign tumor that has cartilage is a bony projection covered by cartilage called an osteochondroma. These benign tumors rarely develop into cancer. There is a slightly greater chance of developing cancer in people who have many of these tumors, but this is not yet common.

Chondrosarcomas are classified by grade, which measures how quickly they grow. The rating for the pathologist (a specially trained to examine and diagnose tissue samples under a microscope doctor) is assigned. The lower the level, the slower the cancer grows. When a cancer is slow growing, the possibility of spreading is minor and so the prognosis is better. Most chondrosarcomas are either low grade (grade I) or intermediate grade (grade II). High grade (grade III) chondrosarcomas, which are most likely to spread, are less common.

Some chondrosarcomas have distinctive features under a microscope. These variants of chondrosarcoma may have a different prognosis (outlook) than usual chondrosarcomas.

(Dee dih-feh-REN-shee-AY-ted) you dedifferentiated chondrosarcoma chondrosarcoma typical start but then some parts of the change in tumor cells as a high-grade sarcoma (eg high-grade forms fibrous histiocytoma malignant [SU-tee-oh-sy-TOH-muh], osteosarcoma, or fibrosarcoma). This variant of chondrosarcoma tends to occur in older patients and is more aggressive than usual chondrosarcomas.
Clear cell chondrosarcoma are rare and grow slowly. Rarely spread to other parts of the body unless they have already returned several times in the original location.
Mesenchymal chondrosarcoma (meh-ZEN-kih-mul) can grow rapidly, but like Ewing tumor, are sensitive to treatment with radiation and chemotherapy.

Ewing tumor: Ewing tumor is the third most common primary bone cancer and the second most common in children, adolescents and young adults. This cancer (also called Ewing's sarcoma) is named after the doctor who first described it in 1921, Dr. James Ewing. Most Ewing tumors develop into bone, but may begin at other tissues and organs. The most common sites for this cancer are the pelvis, chest wall (such as ribs or shoulder blades), and long bones of the legs or arms. This cancer is more common in children and adolescents is rare in adults over 30. Ewing tumors occur most often in white people and are very rare among African Americans and Asian Americans. More detailed information on this type of cancer can be found in our document Ewing family of tumors.

Malignant fibrous histiocytoma: Malignant fibrous histiocytoma (MFH) more often begins in soft tissue (connective tissue such as ligaments, tendons, fat and muscle) than in bone. This type of cancer is also called undifferentiated pleomorphic sarcoma, especially when starting on soft tissues. When MFH occurs in bones, usually affecting the legs (often around the knees) or arms. This cancer occurs most often in older and middle-aged adults and is rare in children. MFH mostly tends to grow locally, but may spread to distant sites such as the lungs.

Fibrosarcoma: This is another type of cancer that develops most often in soft tissue that makes the bones. Fibrosarcoma usually occurs in the elderly and middle-aged adults. The bones of the legs, arms and jaw are the most affected.

Giant cell tumor of bone: This type of primary bone tumor has benign and malignant forms. The (non-cancerous) benign form is the most common. Giant cell bone tumors typically affect the leg (usually near the knees) or arm bones of young adults and middle-aged. They often do not spread to distant sites, but they tend to go back where they started after surgery (this is called local recurrence). This can happen several times. With each repetition, it becomes more likely to spread to other parts of the body as the tumor. Rarely, a malignant bone giant cell tumor spreads to other parts of the body without recourse first locally.

Chordoma: This primary tumor of bone usually occurs at the base of the skull and bones of the spine. It develops most often in adults over 30 years and is twice as common in men as in women. Chordomas tend to grow slowly and often do not spread to other parts of the body, but they often come back in the same area if not eliminated altogether. Lymph nodes, lungs and liver are the most common areas of secondary spread of tumor.

Other cancers that develop in the bones

Non-Hodgkin lymphomas
Non-Hodgkin lymphoma usually develops in the lymph nodes, but sometimes starts in the bone. Primary non-Hodgkin lymphoma of bone is often a widespread disease due to multiple sites in the body are often involved. The picture is similar to other non-Hodgkin lymphomas of the same subtype and stage. It is not treated as a primary bone sarcoma - primary lymphoma of bone in the same way that lymphomas that originate in the lymph nodes occurs.

Multiple myelomas
Multiple myeloma usually develops in the bone, but doctors do not consider it a primary bone cancer, as it develops from the plasma cells in the bone marrow (the soft inner part of some bones). Although cause bone destruction, is no longer a bone cancer it is leukemia. It is a widespread disease. Sometimes, myeloma can be found first as a single tumor (called a plasmacytoma) in a bone, but most of the time it will spread to the marrow of other bones.