While some types of tumors are well-known, desmoid tumors are much less common. Desmoid tumor is a rare disease that affects the connective tissue — or soft tissue — between your joints and muscles. The condition may also be called desmoid-type fibromatosis or aggressive fibromatosis. Although desmoid tumors aren’t cancerous, they’re aggressive and can cause many problems.

Unlike tumors that affect just one organ, desmoid tumors can appear in many different places in the body. In many cases, the tumors form in tissues in or around the abdomen. These are called intra-abdominal tumors and can develop in the abdominal wall or parts of the abdominal cavity, a space in the abdomen that helps to connect organs to each other. Tumors can also form in organs inside the abdomen, like the pancreas. Desmoid tumors can also be extra-abdominal, meaning they form in places outside of the abdomen. This can include tissues in the chest, head, neck, and limbs.

Because desmoid tumors can affect different areas of the body, they can cause many different types of symptoms. While not all desmoid tumors will cause symptoms, some can have a significant impact on your life and may even be life-threatening.

This article will cover the various symptoms that may be caused by desmoid tumors. By learning the warning signs to look out for, you can know when to reach out to your health care provider for answers.

1. Pain

Desmoid tumors can cause significant pain. Unfortunately, getting relief can be difficult — you may find that it doesn’t go away with typical painkillers. If the pain becomes intense, it may negatively affect your daily life. Determining whether pain is caused by a desmoid tumor can be difficult, because the pain can occur in different parts of the body depending on the tumor's location.

On the other hand, some people with desmoid tumors may not have any pain at all. Even if you don’t have pain anywhere in your body, there are other symptoms of desmoid tumors to watch out for.

2. Swelling Near the Tumor

Desmoid tumors may cause a part of your body to become swollen — most likely near where the tumor is located. Depending on the tumor’s location, you may be able to see the swelling or even feel a lump under your skin. You may also notice the area becoming more swollen over time.

If you notice swelling in a part of your body and aren’t sure of the cause, mention this to your doctor — they may perform follow-up tests to confirm a diagnosis.

3. Feeling Sick and Tired

Like many health conditions, desmoid tumors can cause you to feel fatigued (tired). You might also have a general feeling of being sick or unwell. This may be referred to as malaise and is especially linked to intra-abdominal tumors. While there are many reasons you might feel sick or tired, your doctor can help figure out if certain treatments might improve your symptoms.

4. Weight Loss

In many cases, desmoid tumors form in tissues or organs within the abdomen. This can cause problems with the digestive system and may lead to significant weight loss. This may happen suddenly and over a short period of time.

People with desmoid tumors may also lose weight due to cachexia. This is a condition caused by problems with one’s metabolism, leading to a loss of muscle and fat. Unlike normal weight loss, cachexia can cause a person to lose weight even if they’re eating normally. People affected by cachexia may also feel fatigued and not have much of an appetite.

Seek medical attention if you are unable to keep weight on, especially if the weight loss happens rapidly.

5. Difficulty Sleeping

If the pain caused by a desmoid tumor becomes chronic (long-lasting), it can be hard to ignore. Dealing with constant pain may make it harder to get a good night’s rest. Insomnia — or trouble falling and staying asleep — is common for people living with desmoid tumors. Like other symptoms of desmoid tumor, not getting enough sleep will start to take its toll on your quality of life.

6. Problems With Movement

Desmoid tumors might form in the extremities — these can be the arms, legs, or even the feet. Tumors in the extremities can damage the bones, muscles, or nerves in your limbs. This may make it harder to move your arms and legs properly and could even cause you to walk with a limp.

If you have trouble moving your arms and legs, performing normal activities may become difficult. Reach out to your health care provider if you have problems completing your everyday responsibilities.

7. Pins-and-Needles Sensations

If a desmoid tumor gets big enough, it can start to press on the nerves near the location of the tumor. Compression of the nerves can lead to a tingling sensation described as “pins and needles,” similar to when your foot “falls asleep.” This is called paresthesia and is a type of neuropathic pain — that is, pain caused when nerves are affected. Neuropathic pain may be uncomfortable and should be mentioned to your health care provider.

8. Digestive Problems

Intra-abdominal tumors — if they get large enough — can cause organs in the digestive system to not work properly. This can cause problems, such as:

• Nausea
• Vomiting
• Cramps

Desmoid tumors in the abdomen may also cause more severe digestive issues, such as bowel obstruction. Also called an intestinal obstruction, this occurs when a blockage in your intestines prevents you from digesting food properly. A bowel obstruction can lead to uncomfortable digestive problems or a lack of appetite. If the intestines become completely blocked, you may not be able to have a bowel movement at all.

Some intra-abdominal desmoid tumors may lead to intestinal ischemia — a lack of proper blood flow through your intestines. Intestinal ischemia prevents your intestines from working properly and can cause tissue damage to the intestine due to lack of blood flow.

Significant tissue damage to the intestines could lead to intestinal perforation — the formation of holes in the gastrointestinal tract. This can allow stool (poop) to leak out of your digestive system and into your abdomen, increasing your risk of infection. You may also have internal bleeding.

Obstruction, ischemia, and perforation of the intestines are all life-threatening emergencies that need to be treated quickly. If you experience sudden digestive problems or severe abdominal pain, seek medical attention immediately.

9. Anxiety and Depression

People with desmoid tumor may also have a risk for anxiety and depression. The tumors can change your pain perception, interfere with your sleep, and negatively affect your quality of life — all of which can impact your mental health. If you notice feelings of depression or anxiety, tell your doctor. They can refer you to a mental health counselor.

Speak With a Specialist

Anyone living with symptoms of desmoid tumors understands the negative impact they can have. However, because the condition is so rare and symptoms can vary a lot from person to person, diagnosis can be challenging.

You deserve answers. Even though desmoid tumors are not considered cancer, an oncologist (cancer specialist) will likely treat your condition. Someone who specializes in rare soft tissue sarcomas is most likely to be familiar with desmoid tumors. They can work with you to identify suitable treatment options to help relieve your symptoms and improve your outlook.

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 more questions about the symptoms of desmoid tumors? Share them in the comments below, or start a conversation by posting on your Activities page.