What causes soft tissue sarcoma?

Soft tissues include muscle, fat, blood vessels, nerves, tendons, and tissues that support organs. A sarcoma can start when a cell in one of these tissues gains changes that disturb normal growth and repair. The tumour may be a liposarcoma, leiomyosarcoma, or another subtype, depending on the tissue and cell features involved.

Most people cannot identify one event that caused their sarcoma. Some cases are linked with inherited cancer-predisposition syndromes such as Li-Fraumeni syndrome; others involve changes acquired during life. A lump or swelling does not by itself establish sarcoma, because many soft-tissue lumps have non-cancerous causes.

Arrange an assessment for a lump that is growing, deep, firm, fixed, painful, or not settling. A clinician may examine it and arrange imaging. If a biopsy is needed, planning it through a sarcoma-experienced team helps ensure the sample and any later surgery are coordinated.

Share any family pattern of sarcoma, childhood cancers, breast cancer at a young age, or several related cancers with your clinician. This may support genetic counselling. Avoid repeatedly squeezing or attempting to remove a lump yourself.

Seek prompt medical review for a new or enlarging swelling, especially if it limits movement or causes persistent pain. Seek urgent help for sudden severe pain, marked swelling, new weakness or numbness, heavy bleeding, or difficulty breathing or swallowing when a mass is near those structures.

What features of the lump need checking? Which scan is appropriate? Should a specialist team plan the biopsy? Could my family history suggest an inherited syndrome? If the lump is benign, what follow-up should I expect?