Both desmoid tumors and lipomas are growths that can develop in the body, but they’re very different conditions. Desmoid tumors are rare and can be more aggressive, whereas lipomas are common and usually harmless.

This article will help you understand the main similarities and differences between these two types of benign (noncancerous) growths.

What Are Desmoid Tumors and Lipomas?

Desmoid tumors are rare, slow-growing tissue masses. They grow from fibroblasts, cells that make collagen in the connective tissue between your joints, ligaments, and muscles. Desmoid tumors are also called aggressive fibromatosis or deep fibromatosis.

A lipoma is a fatty lump that grows just beneath the skin and can be moved around if you press on it. Lipomas are very common, affecting millions of people worldwide — and they generally aren’t serious.

Similarities Between Desmoid Tumors and Lipomas

Desmoid tumors and lipomas share several similarities, including diagnostic tests, risk factors, and more.

1. Both Types of Growths Are Noncancerous

Both desmoid tumors and lipomas are benign soft tissue tumors. Doctors consider them noncancerous because they don’t spread into nearby tissues or distant organs like cancers do.

2. Imaging Tests Help Diagnose Desmoid Tumors and Lipomas

If you notice a mass in your body, your doctor may do a physical exam. Doing so can help them determine the tumor’s location, see if the tumor can be moved around, and reveal if it’s painful to the touch.

If your doctor finds a suspicious lump, they’ll likely order additional tests. Imaging tests such as ultrasound, computed tomography scans (CT scans), and magnetic resonance imaging scans (MRI scans) are commonly used to diagnose both desmoid tumors and lipomas.

Your doctor may also recommend a biopsy, which involves taking a sample of the tumor for further testing. Biopsies can help determine if the tumor is cancerous or benign and help diagnose both desmoid tumors and lipomas.

3. Desmoid Tumors and Lipomas Can’t Be Prevented

Doctors and researchers haven’t found a way to prevent either desmoid tumors or lipomas. However, in the case of lipomas, you may want to consider cutting back on alcohol. Avoiding alcohol can reduce your risk of developing a condition called Madelung’s disease, which can cause lipomas to develop around the shoulders and neck.

4. Desmoid Tumors and Lipomas Share a Few Risk Factors

Desmoid tumors and lipomas share some of the same risk factors. Familial adenomatous polyposis (FAP) — a genetic syndrome that causes colon polyps — is a risk factor for desmoid tumors. A FAP-related disease known as Gardner syndrome is associated with lipomas. Both desmoid tumors and lipomas are also more common in women, according to Cleveland Clinic.

Each condition also is linked with particular risk factors. Desmoid tumors sometimes develop during or soon after pregnancy or following an injury. Lipomas can be related to health conditions, including:

• Dercum’s disease — A rare disease that causes painful lipomas to develop
• Hereditary multiple lipomatosis — A condition that’s passed down through families and causes multiple lipomas to grow in the trunk and limbs

Differences Between Desmoid Tumors and Lipomas

These two types of benign growths tend to occur in different populations of people and don’t have the same treatments, among other differences.

1. Desmoid Tumors and Lipomas Have Different Treatment Options

Desmoid tumors are treated by sarcoma specialists — oncologists (doctors who specialize in diagnosing and treating cancer) with expertise in treating both desmoid tumors and sarcomas, which are a type of cancer. Lipomas are not treated by oncologists and can often be managed by a primary care physician.

Lipomas usually don't need treatment. However, if they’re very painful, they may be treated with surgery. Lipoma removal is quick, and you can usually go home the same day the surgery is done. Another option for a painful lipoma is to remove the fatty lump using liposuction, which involves a needle and syringe.

Desmoid tumors don’t always require treatment, either. Some tumors grow very slowly and never get big enough to cause problems, and others may shrink on their own and go away. However, your desmoid tumor care team may recommend active surveillance (also called watchful waiting). You’ll have periodic appointments so that your doctor can check if your tumor has grown. If your tumor is progressing or you’re experiencing more troubling symptoms, you might begin treatment.

If you have a desmoid tumor, your care team may recommend medical therapy, such as targeted therapies taken as pills, or sometimes even chemotherapy. Other treatments like radiation therapy, surgery, and cryoablation (using extreme cold to destroy abnormal cells) may be options in specific circumstances.

2. Desmoid Tumors Can Come Back, but Lipomas Usually Don’t

After surgical removal or successful treatment with medication, a desmoid tumor may come back. In contrast, lipomas rarely return. Another can grow in a different spot, but a lipoma doesn't usually return to the same place.

3. Desmoid Tumors Are Rare, Whereas Lipomas Are Common

Desmoid tumors are a rare condition. Each year, for every 1 million people worldwide, just two to four are diagnosed with a desmoid tumor. Lipomas are very common, affecting about one person in every thousand.

4. Desmoid Tumors and Lipomas Develop in Different Locations

Desmoid tumors affect the body’s connective tissue and usually form in the arms, legs, or belly, whereas lipomas can show up anywhere. They’re most common in the back, shoulders, neck, forehead, arms, and legs.

5. Desmoid Tumors and Lipomas Affect Different Age Groups

Generally, desmoid tumors and lipomas occur in different age groups. Desmoid tumors usually affect people ages 20 to 40 and are rare in children and older adults. Lipomas generally occur in 40- to 60-year-olds.

Talk With Others Who Understand

MyDesmoidTumorTeam is the social network for people with desmoid tumors and their loved ones. On MyDesmoidTumorTeam, members come together to ask questions, give advice, and share their stories with others who understand life with desmoid tumors.

Do you have questions about the similarities and differences between desmoid tumors and lipomas? Have you experienced either of these conditions? Share your experience in the comments below, or start a conversation by posting on your Activities page.