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Description
A desmoid tumor is an abnormal growth that arises from connective tissue
, which is the tissue that provides strength and flexibility to structures such as bones, ligaments, and muscles. Affected individuals typically develop a single tumor, although some have multiple tumors. Desmoid tumors most often develop when people are in their 30s or 40s, although they can occur anytime between adolescence and late adulthood.
Tumors that form in the abdomen or abdominal wall are called abdominal desmoid tumors, those that arise from the tissue that connects the abdominal organs are called intra-abdominal desmoid tumors, and tumors found in other regions of the body are called extra-abdominal desmoid tumors. Extra-abdominal tumors occur most often in the shoulders, upper arms, and upper legs.
Desmoid tumors are fibrous, much like scar tissue. They are generally noncancerous (benign) because they do not spread to other parts of the body (metastasize
); however, they can aggressively invade the surrounding tissue and can be very difficult to remove surgically. Desmoid tumors can recur, even after they are removed. In about 20 percent of cases, the tumors shrink or disappear with minimal or no treatment (spontaneously regress).
Desmoid tumors may not cause any signs or symptoms. When they do cause symptoms, the most common one is pain. The pain is often due to the tumor pressing against nearby organs, tissues, or blood vessels. Other signs and symptoms are often caused by growth of the tumor into the surrounding tissue, and they can vary based on the size and location of the tumor. Intra-abdominal desmoid tumors can block the bowel, causing constipation. Extra-abdominal desmoid tumors can restrict the movement of affected joints, making it difficult to move the arms or legs.
Desmoid tumors can also occur in combination with other conditions. Desmoid tumors are found in 10 to 30 percent of people with an inherited form of colon cancer called familial adenomatous polyposis (FAP). These individuals typically develop intra-abdominal desmoid tumors in addition to abnormal growths (called polyps) and cancerous tumors in the colon
. Desmoid tumors that are not part of FAP are described as sporadic.
Frequency
Desmoid tumors are rare, affecting an estimated 2 to 6 per 1 million people worldwide. In the United States, about 1,000 new cases are diagnosed per year. About 10 percent of all desmoid tumors occur in people with FAP. For reasons that are unclear, women develop desmoid tumors more often than men with women accounting for 70 percent of cases.
Causes
Variants (also called mutations) in the CTNNB1 gene account for around 90 percent of sporadic desmoid tumors. Variants in the APC gene cause the desmoid tumors that are associated with FAP. Both genes are involved in an important cell signaling pathway that controls the growth and division (proliferation) of cells and the process by which cells mature to carry out specific functions (differentiation).
The CTNNB1 gene provides instructions for making a protein called beta-catenin. This protein interacts with other proteins to control the activity (expression) of particular genes, which helps promote cell proliferation and differentiation. CTNNB1 gene variants lead to an abnormally stable beta-catenin protein that is not broken down when it is no longer needed. The protein accumulates in cells, where it continues to function and allows uncontrolled cell proliferation and the formation of desmoid tumors.
The protein produced from the APC gene helps regulate the levels of beta-catenin in the cell by attaching (binding) to other proteins to form a complex. When this complex binds to beta-catenin, it helps to break down the protein. Variants in the APC gene cause cells to produce an abnormally short version of the APC protein that is unable to form the complex. As a result, beta-catenin is not broken down and, instead, accumulates in cells. Excess beta-catenin promotes uncontrolled growth and division of cells, causing the formation of polyps and, occasionally, desmoid tumors in people with FAP.
Inheritance
Most desmoid tumors are not inherited. These tumors are caused by variants in genes that occur during a person's lifetime, called somatic variants. Somatic variants in the CTNNB1 gene can cause sporadic desmoid tumors. A somatic variant in one copy of the gene is sufficient to cause the disorder.
An inherited variant in one copy of the APC gene causes FAP and predisposes affected individuals to develop desmoid tumors. FAP is inherited in an autosomal dominant pattern
, which means one copy of the altered APC gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition.
Other Names for This Condition
- Aggressive fibromatosis
- Desmoid fibromatosis
- Desmoid-type fibromatosis
- Familial infiltrative fibromatosis
- Hereditary desmoid disease
- Musculoaponeurotic fibromatosis
Additional Information & Resources
Genetic Testing Information
Genetic and Rare Diseases Information Center
Patient Support and Advocacy Resources
Clinical Trials
Catalog of Genes and Diseases from OMIM
Scientific Articles on PubMed
References
- Cojocaru E, Gennatas S, Thway K, Fisher C, Smrke A, Strauss D, Hayes A, Smith M, Jones RL, Benson C, McVeigh TP. Approach to screening for Familial Adenomatous Polyposis (FAP) in a cohort of 226 patients with Desmoid-type Fibromatosis (DF): experience of a specialist center in the UK. Fam Cancer. 2022 Jan;21(1):69-74. doi: 10.1007/s10689-021-00230-8. Epub 2021 Feb 6. Citation on PubMed
- Escobar C, Munker R, Thomas JO, Li BD, Burton GV. Update on desmoid tumors. Ann Oncol. 2012 Mar;23(3):562-569. doi: 10.1093/annonc/mdr386. Epub 2011 Aug 22. Citation on PubMed
- Huss S, Nehles J, Binot E, Wardelmann E, Mittler J, Kleine MA, Kunstlinger H, Hartmann W, Hohenberger P, Merkelbach-Bruse S, Buettner R, Schildhaus HU. beta-catenin (CTNNB1) mutations and clinicopathological features of mesenteric desmoid-type fibromatosis. Histopathology. 2013 Jan;62(2):294-304. doi: 10.1111/j.1365-2559.2012.04355.x. Epub 2012 Sep 28. Citation on PubMed
- Kasper B, Baldini EH, Bonvalot S, Callegaro D, Cardona K, Colombo C, Corradini N, Crago AM, Dei Tos AP, Dileo P, Elnekave E, Erinjeri JP, Navid F, Farma JM, Ferrari A, Fiore M, Gladdy RA, Gounder M, Haas RL, Husson O, Kurtz JE, Lazar AJ, Orbach D, Penel N, Ratan R, Raut CP, Roland CL, Schut AW, Sparber-Sauer M, Strauss DC, Van der Graaf WTA, Vitellaro M, Weiss AR, Gronchi A; Desmoid Tumor Working Group. Current Management of Desmoid Tumors: A Review. JAMA Oncol. 2024 Aug 1;10(8):1121-1128. doi: 10.1001/jamaoncol.2024.1805. Citation on PubMed
- Lips DJ, Barker N, Clevers H, Hennipman A. The role of APC and beta-catenin in the aetiology of aggressive fibromatosis (desmoid tumors). Eur J Surg Oncol. 2009 Jan;35(1):3-10. doi: 10.1016/j.ejso.2008.07.003. Epub 2008 Aug 21. Citation on PubMed
- Mangla A, Agarwal N, Schwartz G. Desmoid Tumors: Current Perspective and Treatment. Curr Treat Options Oncol. 2024 Feb;25(2):161-175. doi: 10.1007/s11864-024-01177-5. Epub 2024 Jan 25. Citation on PubMed
- Riedel RF, Agulnik M. Evolving strategies for management of desmoid tumor. Cancer. 2022 Aug 15;128(16):3027-3040. doi: 10.1002/cncr.34332. Epub 2022 Jun 7. Citation on PubMed
- Trautmann M, Rehkamper J, Gevensleben H, Becker J, Wardelmann E, Hartmann W, Grunewald I, Huss S. Novel pathogenic alterations in pediatric and adult desmoid-type fibromatosis - A systematic analysis of 204 cases. Sci Rep. 2020 Feb 25;10(1):3368. doi: 10.1038/s41598-020-60237-6. Citation on PubMed
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