Learning you have a desmoid tumor

An early and accurate diagnosis is important

Perhaps you’ve had a strange pain that will not go away, a visible lump under your skin, or a growing discomfort after a pregnancy.1 These are among the many possibilities that could start the process of getting diagnosed with a desmoid tumor. A doctor could even find a desmoid tumor while looking at a completely unrelated issue.2

Because desmoid tumors are so rare and can appear differently from person to person, people do not always get properly diagnosed right away. In fact, desmoid tumors are misdiagnosed approximately 30% to 40% of the time.3

A desmoid tumor may be incorrectly identified as scar tissue or another type of tumor.4,5 That can mean serious delays for some people in getting the care they need. But don’t worry—there are several ways to help get a timely and accurate diagnosis.

Desmoid tumors
are misdiagnosed




of the time3

Let’s describe this disease as it actually is. Because it isn’t benign. It doesn’t metastasize. But it is life altering. It’s life-changing.

DeAnn, patient with a desmoid tumor

DeAnn on a medical exam table

There are several ways to help get a timely and accurate diagnosis

NCCN Guidelines for Patients® provides a roadmap to help patients understand their diagnosis and treatment options. According to the NCCN Guidelines for Patients, it is important that a biopsy be performed. Imaging of the primary site with a CT or MRI will be done as needed.6

Otherwise, an incorrect diagnosis can result in delayed or incorrect treatment. This may lead to unnecessary surgery and risk of complications. Your doctor may choose to perform additional tests as well. If you have questions about getting diagnosed, be sure to ask your care team.

Evaluation and Diagnosis

Medical history and physical exam

A CT scan, MRI, and/or ultrasound to see what’s happening in the body can help doctors understand where the tumor is and whether or not it can be easily removed.7 A radiologist will review the images and write a report. They will send this report to your doctor, who will review these results with you.

Biopsy, or a tissue sample, is needed to diagnose a desmoid tumor. A biopsy is recommended before starting treatment8

Additional tests that may be helpful:8

  • Genetic testing
  • Staining for beta-catenin on biopsy tissue to help doctors diagnose desmoid tumors

Read as much as you can, get yourself informed as best as possible. You have to be your own advocate. 

Melony, patient with a desmoid tumor

Melony standing in a field

Knowledge is power

This Discussion Guide will provide information to help guide your conversations with your medical team.

  1. Cancer.Net. Desmoid tumor: risk factors. Accessed April 16, 2022. https://www.cancer.net/cancer-types/desmoid-tumor/risk-factors.
  2. Cancer.Net. Desmoid tumor: symptoms and signs. Accessed April 16, 2022. https://www.cancer.net/cancer-types/desmoid- tumor/symptoms-and-signs.
  3. Kasper B, Baumgarten C, Garcia J, et al; Desmoid Working Group. An update on the management of sporadic desmoid-type fibromatosis: a European Consensus Initiative between Sarcoma PAtients EuroNet (SPAEN) and European Organization for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG). Ann Oncol. 2017;28(10):2399-2408.
  4. Penel N, Coindre JM, Bonvalot S, et al. Management of desmoid tumors: a nationwide survey of labelled reference centre networks in France. Eur J Cancer. 2016;58:90-96.

  5. Data on file. SpringWorks Therapeutics.
  6. Referenced with permission from the NCCN Guidelines for Patients® for Soft Tissue Sarcoma, V.1.2020. © National Comprehensive Cancer Network, Inc. 2020. All rights reserved. Accessed August 4, 2022. To view the most recent and complete version of the guideline, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use, or application, and disclaims any responsibility for their application or use in any way.
  7. Cancer.Net. Desmoid tumor: diagnosis. Accessed April 15, 2022. https://www.cancer.net/cancer-types/desmoid-tumor/diagnosis.
  8. The Desmoid Tumor Working Group. The management of desmoid tumors: a joint global evidence-based consensus guideline approach for adult and pediatric patients. Accessed April 10, 2022. https://dtrf.org/files/ 2020/02/Desmoid_Paper_2018_A4_RL_Web300-1.pdf.