Tumors that begin in the connective tissues of the body are called sarcomas. The connective tissues include bones, cartilage, fat, muscles, nerves, blood vessels and deep skin tissues. Most sarcomas develop in the arms or legs, but they can be found in any part of the body, including the trunk, head and neck area, internal organs and the area behind the abdominal cavity, known as the retroperitoneum.

Although sarcoma is rare, it can develop in children and adults. In adults, about 1 percent of all solid tumors are diagnosed as sarcoma. It occurs more often in children, with approximately 10 to 15 percent of cancer diagnoses in people under 20 years old being sarcoma.

Sarcomas are divided into two main groups: soft tissue sarcomas and bone sarcomas.

Soft tissue sarcoma

Soft tissue sarcomas are more common than bone sarcomas and can develop in the soft tissues anywhere in the body (see Figure 1). Soft tissue sarcomas occur most frequently in the arms or legs. They are named according to the type of tissue in which they develop. For example, sarcoma that develops in fat tissue is called liposarcoma, and sarcoma that develops in blood vessels is called angiosarcoma.

There are approximately 50 different types of soft tissue sarcoma (see Table 1). Rhabdomyosarcoma is the most common soft tissue sarcoma in children but is rare in adults (see Pediatric Sarcoma).

Table 1. Types of Soft Tissue Sarcoma

Type of Soft Tissue Sarcoma Tissue of Origin Typical Age (Years) Most Common Sites
Most common types
Gastrointestinal stromal tumors
Stroma (supportive connective tissue) of the stomach and intestines
50 and older Wall of the stomach and the small intestine
Leiomyosarcoma Smooth muscle tissue Average is 60 Uterus, small intestine or stomach
Liposarcoma Fat tissue 30-60 Thigh, behind the knee, retroperitoneum
Synovial sarcoma Tissue around joints 15-35 Near the foot, ankle and hand
Undifferentiated pleomorphic sarcoma (previously called
malignant fibrous histiocytoma)
Uncertain 50-70
Leg; may also develop in the retroperitoneum (behind the abdomen) and head and neck
Other types
Alveolar rhabdomyosarcoma Skeletal muscle Adolescents and young adults Large muscles of the trunk, arm, leg
Alveolar soft-part sarcoma Connective tissue Young adults Legs or extremities
rhabdomyosarcoma (previously called pleomorphic
Skeletal muscle Over age 30 Large muscles of the trunk, arm, leg
Angiosarcoma Inner lining of blood vessels 60-70 Skin, breast, liver, spleen, head and neck
Botryoid rhabdomyosarcoma Skeletal muscle Average is 7 Genital region and urinary tract
Desmoid tumors
(aggressive fibromatoses)
Connective tissue that forms tendons and ligaments 10-40
Intra-abdominal mesentery (tissue that attaches organs to the wall of the abdomen), arm, leg
Desmoplastic small round cell tumor
Connective tissue that forms tendons and ligaments Adolescents and young adults Abdomen
Skeletal muscle Under age 10
Anywhere, but often in head and neck, and around the eye
Epithelioid sarcoma Skin 20-39 Arm, hand, feet
Fibrosarcoma Fibrous tissue 35-55 Thigh, knee, arm and trunk
Inner lining of blood vessels
20-40 Soft tissues or internal organs such as liver or lung
Malignant peripheral nerve sheath tumors
Cells that surround a peripheral nerve (nerves that connect the central nervous system — spinal cord and brain) with other parts of the body
20-50 Upper part of the arm and leg, trunk

Bone sarcoma

Bone sarcoma is a tumor that starts in a bone. It is different from cancer that spreads to bone from another site, such as the breast or lung, which is called metastatic cancer. There are three types of primary bone sarcoma (see Figure 2 and Table 2):

  • Osteosarcoma, also called osteogenic sarcoma, is the most common type of bone cancer. Osteosarcoma occurs most often in people 10 to 30 years old and develops primarily in the legs (around the knee) and in the upper arm.
  • Chondrosarcoma, the second most common primary bone cancer, develops inside of bone and is made up of cartilage. Cartilage is fibrous tissue mixed with a gel-like substance, making it softer than bone but harder than most tissues in the body. Chondrosarcoma can occur anywhere in the body where cartilage is present but most frequently develops in the pelvis, legs or arms.
  • Ewing sarcoma is a rare bone sarcoma that occurs more frequently in children and young adults. It usually develops in the pelvis and legs (see Pediatric Sarcoma).

Table 2. Types of Bone Sarcoma

Type of Bone Sarcoma Tissue of Origin Typical Age (Years) Most Common Sites
Most common types
Chondrosarcoma Cartilage 40 and older Pelvis, leg, arm
Ewing sarcoma Bone 10-20 Pelvis, leg
Osteosarcoma Bone 10-30 Leg (near the knee), upper arm (near the shoulder)
Other types
Adamantinoma Bone 20-50 Lower leg
Chordoma Bone 40-70 Skull base, spine, tailbone
Malignant giant cell tumor of bone Bone 20-60 Knee


The symptoms associated with soft tissue sarcoma and bone sarcoma are different. For soft tissue sarcoma, symptoms depend on the location. The first signs of a soft tissue sarcoma may be very subtle. Pain is not a common first presenting symptom, rather the patient may note the presence of a slowly, enlarging, painless mass that may or may not be related to a prior trauma. The trauma would not be the cause of the tumor, rather the source of pain or knowledge of its presence or existence. Some sarcomas, including synovial sarcoma and various fibrous tumors, can cause pain. If the tumor touches a nerve, it may cause pain as well. An abdominal mass is often found with a soft tissue sarcoma in the retroperitoneal area, and pain occurs in about half of people with a soft tissue sarcoma in this site. People with gastrointestinal stromal tumors (GISTs) may have digestive symptoms, such as nausea, vomiting, a feeling of being full after eating a small amount of food or loss of appetite. GISTs are soft tissue sarcomas that form in soft tissues of the gastrointestinal tract, usually in the stomach or small intestine.

Bone sarcomas usually are accompanied by localized pain that becomes progressively severe. Localized soft-tissue swelling may also be present. If the tumor is in the lower extremities, it can cause a painful limp. Movement or weight-bearing of the involved extremity may make pain worse.

Risk factors

Certain factors can increase an individual’s risk of a bone sarcoma or a soft tissue sarcoma. However, there is no known cause of sarcomas.

Among the factors that may raise the risk of a soft tissue sarcoma are previous radiation therapy, genetics (including such inherited diseases as neurofibromatosis type 1, Gardner syndrome, Werner syndrome, tuberous sclerosis, nevoid basal cell carcinoma syndrome, Li-Fraumeni syndrome and retinoblastoma), immune system abnormalities, lymphedema and exposure to chemicals such as vinyl chloride monomer, which is used in making some types of plastics, Agent Orange or dioxin.

Children with osteosarcoma are usually tall for their age, which may indicate this disease could be related to rapid bone growth. It is more common in boys than girls. Other factors that may contribute to the development of osteosarcoma include radiation therapy for a previous cancer; having a previous noncancerous bone disease, including Paget disease of the bone and hereditary multiple osteochondromas (benign bone tumors); or having an inherited cancer syndrome such as a retinoblastoma, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, Bloom syndrome, Werner syndrome or Diamond-Blackfan anemia.

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