Sarcoma: what kind of tumor is it and is it cancer

Sarcoma is not a single diagnosis but a group of tumors of different origins. Below is what is known about sarcomas, how they differ from carcinomas, what types exist, and when a lump in the soft tissues requires attention.

What sarcoma is and cancer of what it is

Sarcoma is a group of malignant tumors arising from actively dividing, so-called immature connective tissue: bone, cartilage, muscle, fat, as well as from the walls of blood and lymphatic vessels. The name goes back to the Greek for "flesh, meat"; on cross-section the tumor has a pinkish-white color resembling fish flesh. Sarcoma is not tied to an organ, so the question "cancer of what" does not strictly apply to it: the starting point is the tissue, not the organ.

Its frequency is low — about 1% of all malignant tumors — but in terms of the number of deaths sarcomas rank second after cancer. The reason is rapid infiltrative growth, recurrences after removal, and early metastases: when located in the limbs, head, neck, and trunk they more often spread to the lungs, and with tumors of the abdominal cavity — to the liver. Growth is usually faster than that of classic cancer, especially in children.

Sarcomas occur at any age, but the profile differs: leiomyosarcoma, chondrosarcoma, and gastrointestinal stromal tumors are more common in adults, while Ewing sarcoma and osteosarcoma occur in children and young people.

How sarcoma differs from carcinoma

Cancer (carcinoma, adenocarcinoma) grows from epithelial cells: from the epithelium lining organ cavities, from the covering epithelium of the skin and mucous membranes, or from glandular epithelium. Sarcoma originates from connective tissue. What remains common are the features of malignancy: infiltrative growth, recurrences, early metastasis. There is also a rare mixed variant — carcinosarcoma.

The simplification that sarcoma is "just another cancer" is inaccurate: carcinoma is classified by organ or covering tissue, whereas sarcoma is classified by tissue of origin; these are different groups of diseases with different statistics.

Main types: bone sarcoma, soft tissue sarcoma, myosarcoma, synovial

Bone sarcomas — osteogenic sarcoma, Ewing sarcoma, chondrosarcoma, and rarer forms. The peak incidence of bone neoplasms occurs in the second decade of life: 3 cases per 100,000 population, and in people over 30 years — 0.2 per 100,000.

Soft tissue sarcomas (muscles, tendons, fat, vessels) account for about 1% of all oncological diseases. In Russia the incidence remains at the level of 2.13 and 1.83 cases per 100,000 among men and women; in childhood these tumors rank fifth in frequency. Myosarcoma is a sarcoma of muscle tissue; synovial sarcoma is a separate form.

Distribution of forms among soft tissue sarcomas:

• malignant fibrous histiocytoma — 29.4%;
• liposarcoma — 15%;
• leiomyosarcoma — 11.6%;
• synovial sarcoma — 10.5%;
• rhabdomyosarcoma — 4.8%.

The causes have not been precisely established. Risk factors include contact with certain chemicals, prior radiation therapy, and hereditary genetic diseases; the list of possible causes also includes radiation, oncogenic viruses, malignant transformation of benign tumors, and injuries.

Kaposi sarcoma: a separate form

In the general classification, Kaposi sarcoma is singled out as an independent form — along with angiosarcoma, lymphangiosarcoma, fibrosarcoma, and liposarcoma. Among the causes of sarcomas, oncogenic viruses are cited, in particular human herpesvirus HHV-8. There is no universal description of the initial stage for sarcomas: the picture and course depend on the biological characteristics of the cells of origin and the location of the tumor.

How sarcoma is diagnosed and when to see a doctor

Soft tissue sarcoma manifests as a lump or swelling. As it spreads, the tumor compresses nerves and organs — hence pain or difficulty breathing. The diagnosis is made with a biopsy.

The reason for a consultation is a lump or swelling in the soft tissues, especially with pain or difficulty breathing.

A neoplasm in the soft tissues is not in itself a reason to call an ambulance; 103/112 — for pronounced difficulty breathing.

The material is for reference and does not replace a doctor's consultation: the decision on whether examination is needed is made by a specialist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer