How a Desmoid Tumor Is Diagnosed

Desmoid tumors are a rare type of benign (noncancerous) tumor. Some grow for months or years before a person notices them. Others cause symptoms such as pain or swelling. 

While there are no at-home testing or screening options, it’s important to be aware of the signs and symptoms you should report to your healthcare provider. Doctors will most likely order blood and imaging tests to guide their next step. However, a biopsy (removing a sample tissue for further examination in a lab) is needed to definitively diagnose a desmoid tumor. 

Radiology technician helping patient

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Self-Checks/At-Home Testing

There are no standard screening or in-home tests available for desmoid tumors. If you have signs and symptoms, they should be examined by your healthcare provider. Signs and symptoms that may indicate a desmoid tumor include:


Unusual or new lumps are often the first sign that people notice at home. They are fibrous, firm lumps that feel like scar tissue. They either may cause pain or be completely painless. 

They can grow in any area with soft tissue, but the most common areas include:

  • Intra-abdominal (stomach area)
  • Neck
  • Shoulders
  • Upper arms
  • Upper legs

Sometimes the lumps sit under the skin, while others are less obvious. Most of these tumors grow slowly over time, but some do grow more rapidly. A small percentage may go dormant or shrink without any treatment. Tumors that are more than 2 inches—or larger than a golf ball—should be reported to your healthcare provider.


Pain is the most common symptom and ranges from uncomfortable to sharp, stinging, or burning pain. Tumors that grow just beneath the surface of the skin may be slightly uncomfortable or painless. Variations in pain occur based on the size and location of the tumor. 

The pain is usually persistent and chronic unless the tumor is growing quickly. Tumors that grow rapidly or aggressively may cause acute, or sudden, pain.

Other Symptoms

  • Tingling: As a desmoid tumor grows, it may press on surrounding nerves or blood vessels and create a tingling feeling some describe as "pins and needles."
  • Swelling: Swelling is often seen in the arms, legs, chest, neck, or abdomen and may worsen at night.  
  • Sleep loss: Sleep loss may occur due to discomfort, pain, tingling, swelling, or anxiety. 
  • Decreased mobility: Tumors in the leg may affect the surrounding joints and cause problems moving the legs, arms, hands, or feet.  
  • Gastrointestinal (GI) problems: Desmoid tumors in the abdomen can cause a bowel obstruction. If this occurs, symptoms include bloating, constipation, nausea, vomiting, and abdominal pain.

History and Physical Examination 

Your healthcare provider will review your medical record and ask you questions about your history and your symptoms. Keeping a logbook with your medical information can help you prepare for your doctor’s appointment. A logbook might include a list of medications, allergies, hospitalizations, surgeries, and any other notes or questions you want to remember. A few questions the healthcare team may ask you include:

  • When was the first time you noticed the lump, pain, or any other symptom?
  • Is the symptom constant, or does it come and go?
  • Does the pain worsen during any specific activity?
  • Has the tumor grown or shrunk?
  • Has anyone in your family had a desmoid tumor or any other tumor?

The next step is a thorough physical examination of the area surrounding the lump, swelling, or pain. Your primary doctor will most likely perform this first exam. If needed, they may refer you to a specialist such as a surgeon or a radiologist for further evaluation. If a desmoid tumor is suspected, ask your referring physician if the specialist has experience with this type of tumor.

While desmoid tumors are not cancerous, they are sometimes treated with cancer medications. Depending on your biopsy results, the doctor may also refer you to an oncologist or cancer doctor. 


If your healthcare provider suspects a desmoid tumor based on your history and physical, the doctor may order an imaging test such as an X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI), bone scan, or positron-emission tomography (PET) scan. A specialized radiology technologist or nurse will usually perform the imaging test. The radiologist will review the images and provide a report about the size and appearance of the tumor and its effect, if any, on nearby structures.

Noninvasive imaging tests are:

  • X-rays: X-rays use electromagnetic energy to produce images of bones and internal organs.
  • Ultrasound: Ultrasound is a technique that uses sound waves to create a picture.
  • CT (or CAT) scan: This technique combines X-rays and the computer to provide detailed images. It takes a series of images called “slices” for three-dimensional images. 
  • MRIs: MRIs use a strong magnetic field to produce a two- or three-dimensional detailed image of an internal structure.
  • PET scans: This technique may be used to evaluate if the tumor is spreading or damaging the body in any way. PET scans do not show much detail of the tumor itself, so they are often combined with a CT scan.

Incidental Findings

There are documented cases of desmoid tumors found unexpectedly through imaging tests done for reasons unrelated to the tumor.

Labs and Tests 

While blood tests are not used to make a definitive diagnosis for a desmoid tumor, they are routinely ordered to help the healthcare team rule out other conditions. Standard blood work includes a CBC and chemistry. They may also order specialized testing such as tumor markers


A biopsy is a procedure in which a tissue sample of the lump is obtained to gain a definitive diagnosis. The tissue sample is reviewed in a lab by pathologists, doctors who examine body tissues under the microscope. The biopsy is often performed by a radiologist, general surgeon, or a specialized surgeon such as a surgical oncologist. 

Two types of biopsy techniques may be used to obtain the tissue sample and are:

Needle Biopsy

A needle biopsy is a procedure used to get a sample of the lump using local anesthetic (numbing medication placed near the site of the biopsy). Doctors often use imaging guidance such as ultrasound to make sure the needle is in the right place. 

These biopsy sites have a small risk of bleeding and infection. There may also be some discomfort at the site after the numbing medicine wears off. This is usually relieved by over-the-counter (OTC) pain relievers. Ask your provider which is best for you. 

Surgical Biopsy

A surgical biopsy is performed under general anesthesia (medication to put you in a sleep-like state) to minimize discomfort. After the surgery, you will receive discharge instructions specific to the biopsy site. However, it’s helpful to ask your healthcare providers about postsurgical pain relief and risk factors in advance. 

How to Prepare for a Biopsy

  • Your healthcare team may ask you to stop taking any blood-thinning medications such as Coumadin (warfarin) or aspirin a few days before the procedure. 
  • Tell the team about any medications, including herbal supplements, vitamins, prescriptions, and OTC medications. 
  • Tell your provider if you may be pregnant or have had any recent illnesses.
  • Arrange for someone to drive you home, especially if you have a surgical biopsy and have been under anesthesia.

Differential Diagnosis

Your healthcare team will consider all possible diagnoses with your initial history and physical, which they narrow down with the imaging results. If a tumor is present on the imaging tests, they will most likely send you to a specialist for a biopsy. While blood work is not necessary to diagnose a desmoid tumor, healthcare providers will often order it to rule out different types of tumors and cancer. 

A conclusive diagnosis of a desmoid tumor requires a biopsy that a pathologist evaluates. They look under the microscope for specific cells and characteristics that indicate particular types of tumors, including desmoid tumors. 

A Word From Verywell 

If you are experiencing any signs and symptoms of a desmoid tumor, contact your healthcare provider. While these tumors are rare, early diagnosis and intervention are always best for any healthcare concern. 

Waiting on a diagnosis can be stressful. If your existing symptoms change or become more uncomfortable, inform your healthcare team. A doctor may be able to provide supportive care as you wait for a definitive diagnosis or permanent treatment. 

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Brandi Jones, MSN-ED RN-BC
Brandi is a nurse and the owner of Brandi Jones LLC. She specializes in health and wellness writing including blogs, articles, and education.