A sarcoma is a malignant tumor, a type of cancer that arises from cells of mesenchymal (connective tissue) origin.

[2][3] 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.

[6] The word sarcoma is derived from the Greek σάρκωμα sarkōma 'fleshy excrescence or substance', itself from σάρξ sarx meaning 'flesh'.

In the United States, the American Joint Committee on Cancer (AJCC) publishes guidelines that classify the subtypes of sarcoma.

[10] Exposure to alkylating agents, such as those found in certain cancer chemotherapeutic medicines, also increases the risk of bone sarcoma.

[2] Most soft-tissue sarcomas arise from what doctors call "sporadic" (or random) genetic mutations within an affected person's cells.

[3] Imaging studies are critically important in diagnosis, and most clinicians will order a plain radiograph (X-ray) initially.

[3] As with bone sarcomas, definitive diagnosis requires biopsy of the tumor with evaluation of histology by a trained pathologist.

[2][4] With sarcomas, staging requires a determination of whether the tumor has grown into surrounding tissues ("local invasion"), as well as imaging to determine whether it has spread (a process known as "metastasis") to lymph nodes (forming "nodal metastases") or to other tissues or organs in the body (forming "distant metastases").

[4] Like some other cancers, sarcomas are assigned a grade (low, intermediate, or high) based on the appearance of the tumor cells under a microscope.

[15] Since high-grade tumors are more likely to undergo metastasis (invasion and spread to locoregional and distant sites), they are treated more aggressively.

[17] As of March 2019[update], the USPSTF does not recommend screening for sarcoma,[17] possibly because it is a very rare type of cancer (see Epidemiology below).

[18] However, patients with some inherited conditions, such as neurofibromatosis, may benefit from screening for development of cancers from pre-existing benign tumors called neurofibromas.

[3][19] Limb-sparing surgery, as opposed to amputation, can now be used to save the limbs of patients in at least 90% of extremity (arm or leg) sarcoma cases.

As a result, high dose chemotherapy with stem cell rescue is generally considered appropriate only in the research setting.

[2] In 2016, scientists reported the discovery of an osteosarcoma tumor in a 1.6–1.8 million-year-old fossil from the skeleton of the now-extinct hominin species Australopithecus sediba, making it the earliest-known case of human cancer.

[3] One new type of therapy still under investigation is the use of cancer immunotherapy (e.g., immune checkpoint inhibitors like anti-PD1, anti-PDL1, and anti-CTLA4 agents) to treat sarcomas.

[32] These drugs are not yet FDA- or other regulator-approved treatment, except PDL1 inhibitor atezolizumab for the ultra-rate diagnosis of alveolar soft part sarcoma.

Many YouTubers have raised awareness and donated to charities such as the Sarcoma Foundation of America after Technoblade's diagnosis and passing.

[37] Kimberley Nix, a Canadian physician, chronicled her journey with undifferentiated pleomorphic sarcoma, from her diagnosis to eventual death, on TikTok under the username @cancerpatientmd.