Print OverviewMyxofibrosarcoma is a type of cancer that begins in the connective tissue. It tends to happen in the arms and legs. Myxofibrosarcoma starts as a growth of cells that can grow into healthy body tissue. Myxofibrosarcoma might cause a lump under the skin that grows slowly. It often isn't painful. This cancer happens most often in older adults. Myxofibrosarcoma is a type of soft tissue sarcoma. Soft tissue sarcomas are cancers that happen in the soft tissues that connect, support and surround other body structures. Products & ServicesA Book: Mayo Clinic Family Health BookNewsletter: Mayo Clinic Health Letter — Digital EditionShow more products from Mayo Clinic SymptomsSymptoms of myxofibrosarcoma include: A painless lump on an arm or leg. A lump that grows slowly. Myxofibrosarcoma most often starts in the leg. It rarely starts in the abdomen, where other kinds of sarcomas tend to grow. When to see a doctorMake an appointment with a doctor or other healthcare professional if you have any symptoms that worry you. Request an appointment CausesThe cause of myxofibrosarcoma often isn't known. This cancer starts as a growth of cells in the connective tissue. Myxofibrosarcoma happens when cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to grow and multiply quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells. The cancer cells can form a lump that may grow into healthy body tissue. Risk factorsThe risk of myxofibrosarcoma is higher in adults. This cancer happens most often in adults ages 50 to 70. It is rare in people under age 30. There is no way to prevent myxofibrosarcoma. By Mayo Clinic Staff Request an appointment Diagnosis & treatment Jan. 17, 2025 Print Living with myxofibrosarcoma? Connect with others like you for support and answers to your questions in the Sarcoma support group on Mayo Clinic Connect, a patient community. Sarcoma Discussions Does anyone have chondrosarcoma? 23 Replies Sat, Jan 18, 2025 chevron-right How do you, as a parent, deal with the anger? Son has sarcoma 9 Replies Sat, Jan 18, 2025 chevron-right GNET Sarcoma-Gastrointestinal Neuroectodermal Tumors 15 Replies Thu, Jan 16, 2025 chevron-right See more discussions Show references Roland CL, et al. Myxofibrosarcoma. Surgical Oncology Clinics of North America. 2016; doi:10.1016/j.soc.2016.05.008. Goldblum JR, et al. Borderline and malignant fibroblastic/myofibroblastic tumors. In: Enzinger and Weiss's Soft Tissue Tumors. 7th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Dec. 7, 2021. Cameron AM, et al. Management of soft tissue sarcoma. In: Current Surgical Therapy. 13th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Feb. 15, 2022. Radaelli S, et al. Treatment strategies and outcomes of primary myxofibrosarcomas in a large patients cohort. European Journal of Surgical Oncology. 2022; doi:10.1016/j.ejso.2022.01.003. Vanni S, et al. Myxofibrosarcoma landscape: Diagnostic pitfalls, clinical management and future perspectives. Therapeutic Advances in Medical Oncology. 2022; doi:10/1177/17588359221093973. Soft tissue sarcoma. Dorland's Medical Dictionary Online. https://www.dorlandsonline.com. Accessed Dec. 20, 2024. Myxofibrosarcoma. National Cancer Institute. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/myxofibrosarcoma. Accessed Dec. 20, 2024. Related Associated Procedures Cancer treatment Chemotherapy CT scan MRI Needle biopsy Radiation therapy Show more associated procedures Products & Services A Book: Mayo Clinic Family Health Book Newsletter: Mayo Clinic Health Letter — Digital Edition Show more products and services from Mayo Clinic MyxofibrosarcomaSymptoms &causesDiagnosis &treatmentDoctors &departments Advertisement Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. Advertising & Sponsorship Policy Opportunities Ad Choices Mayo Clinic Press Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press. NEW: Listen to Health Matters Podcast - Mayo Clinic PressNEW: Listen to Health Matters PodcastMayo Clinic on Incontinence - Mayo Clinic PressMayo Clinic on IncontinenceThe Essential Diabetes Book - Mayo Clinic PressThe Essential Diabetes BookMayo Clinic on Hearing and Balance - Mayo Clinic PressMayo Clinic on Hearing and BalanceFREE Mayo Clinic Diet Assessment - Mayo Clinic PressFREE Mayo Clinic Diet AssessmentMayo Clinic Health Letter - FREE book - Mayo Clinic PressMayo Clinic Health Letter - FREE book CON-20357210 Patient Care & Health Information Diseases & Conditions Myxofibrosarcoma