Risk factors

Factors that may increase the risk of desmoid tumors include:

• Young adult age. Desmoid tumors tend to occur in younger adults in their 20s and 30s. This tumor is rare in children and older people.
• A genetic syndrome that causes many colon polyps. People with familial adenomatous polyposis (FAP) have an increased risk of desmoid tumors. FAP is caused by a gene mutation that can be passed down from parents to children. It causes numerous growths (polyps) in the colon.
• Pregnancy. Rarely, a desmoid tumor may develop during or soon after pregnancy.
• Injury. A small number of desmoid tumors develop in people who've recently had an injury or surgery.