Sarcoma

Some sicknesses grow in the body.

These can grow in bones. They can also grow in muscle. They can grow in fat, too. This is a rare kind of sickness. It can happen to kids. It can happen to adults.

Some lumps may not hurt at all. Other lumps might cause pain in the bones. Doctors use special tools to look inside. They can see where the sickness is. This helps them help the person get well.

A sarcoma is a rare type of cancer. It starts in connective tissues. These tissues hold our bodies together. This includes bone and muscle. It also includes fat and cartilage.

Most cancers are not sarcomas. They only make up about 1% of adult cases. They make up 15% of childhood cancer cases. Doctors group them into two main types. One type is bone sarcoma. The other is soft-tissue sarcoma.

Symptoms can change based on the type. Bone sarcomas might cause swelling. They can also cause bone pain at night. Soft-tissue sarcomas often feel like firm lumps. These lumps might not hurt at all.

Doctors use many tools to find them. They may use an X-ray to look at bones. They might use an MRI to see soft parts. To be sure, a doctor must take a biopsy. This is when they take a tiny piece of the tissue. A specialist looks at it under a microscope. They check the grade of the cells. This tells them how fast the cancer might spread.

A sarcoma is a rare type of cancer. It starts in the connective tissues of the body. These tissues help hold everything together. This includes things like bone, muscle, and fat. It also includes cartilage and vascular tissues.

Most cancers are not sarcomas. They make up about 1% of all adult cancer cases. However, they make up 15% of childhood cancer cases. The name comes from a Greek word meaning "fleshy substance."

Doctors group these cancers into two main ways. The first group is bone sarcomas. These grow in the hard parts of the body. The second group is soft-tissue sarcomas. These grow in the softer parts like muscle or fat. There are many different subtypes within these groups. For example, osteosarcoma is a type of bone sarcoma. Liposarcoma is a type of soft-tissue sarcoma.

Scientists study how these cells change. Sometimes, parts of chromosomes move or fuse together. This is called a translocation. In Ewing sarcoma, part of chromosome 11 fuses with part of chromosome 22. This can create abnormal proteins in the body. In other cases, like liposarcoma, cells might have extra copies of certain genes. These changes can lead to the growth of a tumor. Some types, like Kaposi sarcoma, are caused by a virus.

Many factors can increase the risk of these cancers. Some people are born with certain genetic syndromes. These include Li-Fraumeni syndrome and RB1 gene mutations. Exposure to certain things can also play a role. This includes exposure to ionizing radiation. Some people might also be exposed to chemicals like vinyl chloride. These things are linked to different types of sarcoma. Doctors track these risks to help people stay healthy.

Finding a sarcoma can be a big job for doctors. They often start with a physical exam. For bone sarcomas, they might see swelling or pain at night. For soft-tissue types, they might find a firm lump. Doctors use imaging tools like X-rays or MRIs to look inside. They also use CT scans to see how far a cancer has spread. This is called staging. To be sure, a doctor must perform a biopsy. This means they take a tiny piece of tissue to look at under a microscope.

A sarcoma is a rare type of cancer that begins in mesenchymal cells. These are the cells that form connective tissues throughout the body. Because they originate in these specific cells, sarcomas grow in parts like bone, cartilage, muscle, fat, or vascular tissues.

While there are five main types of cancer classified by cell origin, sarcomas are much less common than carcinomas. In adults, sarcomas represent only about 1% of all cancer diagnoses. However, they are more frequent in children, making up 15% of childhood cancer cases. The name comes from the Greek word for a "fleshy excrescence."

Doctors usually divide sarcomas into two major groups. The first group is bone sarcomas, which grow in the skeletal system. The second group is soft-tissue sarcomas, which grow in the body's softer structures. Each group contains many different subtypes. For example, osteosarcoma is a type of bone sarcoma. Liposarcoma is a subtype of soft-tissue sarcoma that involves fat cells.

There are also primary and secondary tumors. A primary sarcoma starts in the connective tissue itself. A secondary or metastatic tumor occurs when cancer from another organ, like the lungs or breast, spreads to the connective tissue.

Many different subtypes exist within these two groups. The American Joint Committee on Cancer (AJCC) provides guidelines for classifying these subtypes. Bone sarcomas include varieties like chondrosarcoma, angiosarcoma, and chordoma. Soft-tissue sarcomas include many types, such as leiomyosarcoma, rhabdomyosarcoma, and synovial sarcoma. Some subtypes are even more specific. For instance, liposarcoma includes varieties like myxoid sarcoma and dedifferentiated liposarcoma. This complex classification helps doctors understand exactly which tissue is affected.

Scientists are still learning the exact molecular changes that cause these cancers. Sometimes, a chromosomal translocation occurs. This is when parts of two different chromosomes break and fuse together. In Ewing sarcoma, part of chromosome 11 fuses with part of chromosome 22. This creates an abnormal protein from the EWSR1 gene. In dermatofibrosarcoma protuberans, the COL1A1 gene fuses with the PDGFRB gene. This causes over-active signaling that promotes cell division. Other types, like liposarcoma, may involve an amplification of chromosome 12. This means the cells have extra copies of cancer-promoting genes called oncogenes.

Several risk factors are linked to the development of sarcomas. Some people are born with inherited genetic syndromes. Examples include Li-Fraumeni syndrome, neurofibromatosis type 1, and RB1 gene mutations. Exposure to certain environmental factors can also increase risk. Ionizing radiation, such as from previous radiation therapy, is a known factor. For soft-tissue sarcomas, exposure to chemicals like arsenic or vinyl chloride is linked to angiosarcoma. Additionally, the Kaposi sarcoma is caused by the Kaposi sarcoma-associated herpesvirus (HHV-8). These diverse causes explain why sarcomas appear in different ways in different people.

Diagnosing a sarcoma requires several careful steps. Doctors often start with a physical exam to check for symptoms. Bone sarcomas might cause pain at night or swelling. Soft-tissue sarcomas often appear as firm, painless lumps. Doctors use imaging tools like X-rays, MRI, or CT scans to see the tumor. They may also use a radioisotope bone scan to check for spread. However, a definitive diagnosis requires a biopsy. During a biopsy, a pathologist examines a tissue sample under a microscope. This is the only way to be certain of the specific subtype.

Once diagnosed, doctors must perform staging and grading. Staging determines how advanced the cancer is. It looks at tumor size and whether there is local invasion or metastasis. Metastasis is when the cancer spreads to lymph nodes or distant organs, like the lungs. Grading describes how aggressive the cells look under a microscope. Low-grade sarcomas are less aggressive, while high-grade sarcomas are more likely to spread. Staging and grading are vital because they help doctors choose the best treatments. For example, high-grade tumors often require a combination of surgery, chemotherapy, and radiation.

Understanding these details has led to significant medical progress. In the past, the long-term survival rate for children with localized osteosarcoma was only about 20%. Because doctors discovered that many sarcomas are sensitive to chemotherapy, those numbers have changed. Today, the survival rate for those patients has risen to between 60% and 70%. This progress shows how studying the specific mechanisms of cancer can save lives. By identifying the exact type and grade, medical teams can fight these rare diseases more effectively.