A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal (connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sarcomas can arise in any of these types of tissues. As a result, there are many subtypes of sarcoma, which are classified based on the specific tissue and type of cell from which the tumor originates. Sarcomas are primary connective tissue tumors, meaning that they arise in connective tissues. This is in contrast to secondary (or "metastatic") connective tissue tumors, which occur when a cancer from elsewhere in the body (such as the lungs, breast tissue or prostate) spreads to the connective tissue. Sarcomas are one of five different types of cancer, classified by the cell type from which they originate. The word sarcoma is derived from the Greek 'fleshy excrescence or substance', itself from σάρξ meaning 'flesh'.
Classification
Sarcomas are typically divided into two major groups: bone sarcomas and soft-tissue sarcomas, each of which has multiple subtypes. In the United States, the American Joint Committee on Cancer (AJCC) publishes guidelines that classify the subtypes of sarcoma. These subtypes are as follows:
Subtypes of bone sarcoma
Osteosarcoma
Chondrosarcoma
Poorly differentiated round/spindle cell tumors (includes Ewing sarcoma) Hemangioendothelioma Angiosarcoma Fibrosarcoma/myofibrosarcoma Chordoma Adamantinoma Other: Liposarcoma Leiomyosarcoma Malignant peripheral nerve sheath tumor Rhabdomyosarcoma Synovial sarcoma Malignant solitary fibrous tumor.
Subtypes of soft-tissue sarcoma
Liposarcoma (includes the following varieties: atypical lipomatous tumor/well-differentiated liposarcoma, dedifferentiated liposarcoma, myxoid sarcoma, pleomorphic liposarcoma, and myxoid pleomorphic liposarcoma Atypical lipomatous tumor Dermatofibrosarcoma protuberans (includes pigmented varieties) Dermatofibrosarcoma protuberans, fibrosarcomatous Giant cell fibroblastoma Malignant solitary fibrous tumor Inflammatory myofibroblastic tumor Low-grade myofibroblastic sarcoma Fibrosarcoma (includes adult and sclerosing epithelioid varieties) Myxofibrosarcoma (formerly myxoid malignant fibrous histiocytoma) Low-grade fibromyxoid sarcoma Giant cell tumor of soft tissues Leiomyosarcoma Malignant glomus tumor Rhabdomyosarcoma (includes the following varieties: embryonal, alveolar, pleomorphic, and spindle cell/sclerosing) Hemangioendothelioma (includes the following varieties: retiform, pseudomyogenic, and epithelioid) Angiosarcoma of soft tissue Extraskeletal osteosarcoma Gastrointestinal stromal tumor, malignant (GIST) Malignant peripheral nerve sheath tumor (includes epithelioid variety) Malignant Triton tumor Malignant granular cell tumor Malignant ossifying fibromyxoid tumor Stromal sarcoma not otherwise specified Myoepithelial carcinoma Malignant phosphaturic mesenchymal tumor Synovial sarcoma (includes the following varieties: spindle cell, biphasic, and not otherwise specified) Epithelioid sarcoma Alveolar soft part sarcoma Clear cell sarcoma of soft tissue Extraskeletal myxoid chondrosarcoma Extraskeletal Ewing sarcoma Interdigitating dendritic cell sarcoma Desmoplastic small round cell tumor Extrarenal rhabdoid tumor Perivascular epithelioid cell tumor, not otherwise specified Intimal sarcoma Undifferentiated spindle cell sarcoma Undifferentiated pleomorphic sarcoma Undifferentiated round cell sarcoma Undifferentiated epithelioid sarcoma Undifferentiated sarcoma, not otherwise specified.
Signs and symptoms
Symptoms of bone sarcomas typically include bone pain, especially at night, and swelling around the site of the tumor.
Symptoms of soft-tissue sarcomas vary, but they often present as firm, painless lumps or nodules. Gastrointestinal stromal tumors (a subtype of soft-tissue sarcoma) often are asymptomatic, but can be associated with vague complaints of abdominal pain, a feeling of fullness, or other signs of intestinal obstruction.