Desmoid tumors

Overview

Desmoid tumors are growths of cells that form in the body's connective tissue. They most often grow within the belly, arms and legs. Desmoid tumors also are called aggressive fibromatoses. These rare tumors are not cancer.

Some desmoid tumors grow slowly and don't need treatment right away. Others grow more quickly. Tumors that grow quickly or cause symptoms may need to be treated with medicine, surgery or other treatment options.

Desmoid tumors aren't considered to be cancer because they don't spread to other parts of the body. But they can be aggressive, growing into structures and organs nearby. Because of that, people with desmoid tumors often are cared for by doctors who treat cancer, called oncologists.

Symptoms

Symptoms of a desmoid tumor depend on where the tumor is located. Desmoid tumors most often form in the connective tissue of the belly, arms and legs. But they can develop anywhere in the body.

Signs and symptoms of desmoid tumors typically include:

• A mass or area of swelling.
• Pain.
• Cramping and nausea when a desmoid tumor grows in the belly.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any ongoing symptoms that worry you.

Causes

It's not clear what causes desmoid tumors.

Desmoid tumors are growths of cells that form in the connective tissue. Connective tissue surrounds and supports other structures within the body.

Desmoid tumors happen when cells in the connective tissue develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, DNA gives instructions for cells to grow and multiply at a set rate. The instructions also tell the cells to die at a set time. In tumor cells, the DNA changes give different instructions. The changes tell the tumor cells to make many more cells quickly. Tumor cells also can keep living when healthy cells would die. This causes too many cells within the connective tissue.

Risk factors

Anyone can develop desmoid tumors. But factors that may raise the risk of desmoid tumors include:

• A genetic syndrome that causes many colon polyps. People with a condition called familial adenomatous polyposis (FAP) have a higher risk of desmoid tumors. This genetic syndrome is caused by a genetic change that can be passed from parents to children. The condition causes many growths, called polyps, in the colon. Most people with desmoid tumors do not have FAP.
• Injury. A small number of desmoid tumors form in people who've recently had an injury or surgery.
• Pregnancy. Rarely, a desmoid tumor may form during or soon after pregnancy.

Living with desmoid tumors?

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