Symptoms of a desmoid tumor vary depending on its size, stage, and location. How much the tumor invades the nearby tissues, organs, or blood vessels also plays a role. Because these tumors affect flexible and easily moved tissues, they can exist for quite some time without causing noticeable symptoms.  

A desmoid tumor commonly appears as a firm lump. While some are entirely painless, others can cause severe acute (sudden) or chronic (continual) pain. Other common symptoms include tingling, swelling, sleep loss, decreased mobility, and gastrointestinal issues. 

Frequent Symptoms 

Desmoid tumors present themselves in many ways. One person may be asymptomatic, meaning having no symptoms at all, while another feels severe pain. 

This variety of presentation makes all cases and symptoms unique. Not everyone with a desmoid tumor will have all of the following symptoms. However, the most common symptoms include:

Growth Rate of a Desmoid Tumor

An interesting aspect of desmoid tumors is that they can become dormant or shrink without any treatment. Some tumors grow very slowly over time, while a smaller percentage grow rapidly and become aggressive.

  • A firm lump: Desmoid tumors are benign tumors that are fibrous and can feel like scar tissue or a firm lump. Intra-abdominal (stomach area) tumors develop in the tissues connecting the abdominal organs. Extra-abdominal tumors, found in areas other than the abdomen, occur in the neck, shoulders, upper arms, and upper legs. While these areas are the most common, tumors can grow in any soft tissue in the body.
  • Pain: Tumors that grow just beneath the surface of the skin may be slightly uncomfortable or completely painless. However, pain becomes a common symptom as the tumor grows and pushes against nearby tissues, organs, or blood vessels. The discomfort level depends on the size, stage, and location of the tumor.
  • Swelling: The soft tissue in which the tumor is growing may start to swell. Swelling is most often seen in the arms, legs, chest, neck, or abdomen and may worsen at night.
  • Sleep loss: Loss of sleep may occur due to discomfort, pain, tingling, swelling, or anxiety.
  • Tingling: As the tumor grows, it may press on nerves or blood vessels. This pressure can cause tingling, which some describe as a feeling of “pins and needles.”
  • Decreased mobility: Tumors in the leg can cause limping. They can also affect the surrounding joints and cause difficulty moving the arms, hands, legs, or feet.
  • Gastrointestinal issues: Intra-abdominal tumors may not be noticeable until the tumor starts pressing on an organ and causes abdominal pain. They can also cause bloating, fevers, constipation, and vomiting.

Pain in Children or Nonverbal Adults

Types of Pain

  • Chronic pain: A desmoid tumor can cause nerve pain, which is called neuropathic pain. Neuropathic pain develops when the tumor presses on surrounding nerves. This pressure disrupts the nerve’s normal transmission of pain signals to the nervous system. Those with neuropathic pain describe it as a sharp, stinging, or burning sensation. This pain is usually chronic and can be intense.
  • Acute Pain: While desmoid tumors often grow slowly, some grow more quickly and invade the surrounding tissues or blood vessels. This can cause acute or sudden pain.

Recognizing pain in nonverbal adults or young children can be difficult. It can also be challenging when a person has a high tolerance to pain or sensory processing disorders. They may not communicate the discomfort from chronic pain until it becomes intolerable, seemingly acute pain.

When caring for infants, children, or adults who do not communicate well, watch for the following changes in behavior that may indicate pain:

  • Decreased appetite Changes in sleep patterns  Inconsolable cryingGruntingHolding their breathLethargy or exhaustionRestlessnessExtreme fussinessUpset facial expressionsLimping or other limited body movements.

Rare Symptoms

  • Abdominal pain from a splenic infarction: There have been rare cases where an intra-abdominal desmoid tumor causes sudden abdominal pain because it invaded the surrounding organs, such as the spleen. When it invades the spleen, the pain will usually be in the upper left quadrant or area of the abdomen. When the tumor pushes into the artery or blood vessels of the spleen, an occlusion (blockage) occurs. The occlusion shuts off blood flow and oxygen to the spleen, causing tissue death or damage. This is called a splenic infarction which can cause sudden abdominal pain.
  • Chest pain or shortness of breath: While about 50% of desmoid tumors are intra-abdominal, there are rare cases of desmoid tumors growing in the thoracic or chest area. When these tumors press on the vital organs such as the lungs, heart, or major blood vessels, chest pain and shortness of breath can occur.

Complications/Subgroup Indications

The normal function of the intestines is to digest food as it moves from the stomach to the rectum. Food is broken down into usable parts and the intestines turn the rest into feces (stool), which are eliminated through a bowel movements.

Desmoid tumors can cause a bowel obstruction, which is a partial or complete blockage in the small or large intestine. This can be dangerous and cause a tear in the intestine and a severe infection that spreads throughout the body. Blocked bowels can gradually build over time or appear quickly.  A complete blockage is considered an emergency and will require immediate medical attention.

Symptoms that may indicate the initial stages of a bowel obstruction include:

  • Decreased appetite or loss of appetiteCramping in the abdomen Bad breathChanges in bowel movements

The most common effects of a bowel obstruction include:

  • A feeling of fullness in the abdomen
  • Abdominal bloating
  • Abdominal distention or enlargement
  • Constipation
  • Nausea and vomiting
  • Intense abdominal pain and cramping
  • Fever (when infection occurs)

Pregnant Women and Women of Childbearing Age 

Young women of childbearing age have more estrogen in their bodies compared to postmenopausal women. These higher hormone levels create a higher risk of a desmoid tumor for younger women. 

Inflammatory Diseases That Increase the Risk

Certain diseases that cause inflammation of the bowel, such as Crohn’s disease and ulcerative colitis, can increase the risk of bowel obstruction.

Pregnancy-related desmoid tumors are also due to hormone spikes and can develop during pregnancy or after a woman gives birth. These tumors usually develop in the abdominal wall and may also grow around Cesarean section (C-section) scars.

When to Seek Medical Help

While most lumps are not desmoid tumors, it’s important to call the doctor when any lump grows larger than 2 inches (5 centimeters) or if the lump is painful.

You should also see the doctor if you or your loved one is experiencing:

  • Vomiting
  • Limping
  • Swelling
  • Loss of sleep
  • Numbness or tingling that doesn’t go away
  • Persistent bloating and constipation
  • Rectal bleeding or blood in the stool
  • Blood in the urine

When to Seek Emergency Help

If you or your loved one is experiencing debilitating or crippling pain, it’s always best to go to the emergency department to rule out any complications. This includes kidney pain, which is in the lower back on either side of the body.

You should also seek emergency help if you have:

  • A persistent high-grade fever
  • Severe or constant vomiting
  • Difficulty breathing or shortness of breath
  • Chest pain
  • Severe rectal bleeding
  • Persistent blood in the urine
  • Dysuria (inability to urinate)

A Word From Verywell

We understand that having any of these symptoms may be alarming and uncomfortable. However, it’s important to remember that these types of tumors are rare, and most lumps are not desmoid tumors.  

Desmoid Tumors are Rare

Only five or six people out of 1 million are diagnosed with desmoid tumors each year.  

If you are experiencing any of these symptoms, make an appointment with your doctor to rule out any suspicions and to seek symptom relief.

If you are experiencing pain while you are waiting for testing, discuss this with your healthcare team. They may be able to offer supportive care and treat your symptoms while you wait for a definitive diagnosis.

For those currently undergoing treatment, therapy focuses on shrinking desmoid tumors and reducing symptoms, including pain and the need for pain-relieving medications. However, it is essential to report any new or changing symptoms regardless of your stage of treatment.