Aggressive Fibromatosis


Desmoid tumor
Deep Fibromatosis
Musculoaponeurotic Fibromatosis
Nonmetastasizing Fibrosarcoma
Fibromatosis, familial infiltrative
Familial infiltrative fibromatosis
Desmoid disorder, hereditary


Aggressive fibromatosis is a rare condition marked by the presence of desmoid tumors. It commonly develops in the fibrous (connective) tissue of the body that forms tendons and ligaments, usually in the arms, legs or midsection, and also in the head and neck. These tissues of the body connect, support, and surround other body parts and organs. The myofibroblast is the cell considered to be responsible for the development of desmoid tumor. Regardless of its scientific classification, a desmoid tumor can be invasive to surrounding tissues and difficult to control. Desmoid tumors can develop virtually at any body site. Superficial desmoids tend to be less aggressive than deep desmoids (abdominal, extra abdominal, mesenteric). These tumors look like dense scar tissue and just like scar tissue, they adhere tenaciously to surrounding structures and organs, and, thus they are commonly difficult to remove. These tumors often recur, even after apparently complete removal.

Typically, a single tumor develops, although some people have multiple tumors. The tumors can occur anywhere in the body. Tumors that form in the 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.


  • Limping or other difficulty using the legs, feet, arms or hands or other affected part of the body
  • Painless swelling or lump
  • Pain or soreness caused by compressed nerves or muscles
  • Tender subcutaneous mass in lower abdominal wall
  • Firm subcutaneous mass in lower abdominal wall
  • Abnormality of the abdominal wall
  • Sarcoma



The exact cause of desmoid tumor still remains unknown. Desmoid tumors may present sporadically or as a manifestation of a hereditary syndrome called familial adenomatous polyposis (FAP). FAP is a familial cancer predisposition syndrome which, if left untreated at an early age, almost always results in colorectal cancer. Up to 32% of FAP patients will develop desmoid tumors in their lifetime. These desmoid tumors are the result of mutations, or changes, in a gene called adenomatous polyposis coli (APC).

For most affected individuals, desmoid tumors occur in a sporadic manner, meaning that they are not caused by a predisposing genetic disease. People who develop desmoid tumors in a sporadic manner have no other health problems associated with mutations in the APC gene and have no close family members with the tumors. Repeated irritation or trauma to a certain part of the body, including surgical trauma, has been theorized to increase the risk of desmoid tumor occurrence. Estrogen also seems to play a role in the development of desmoid tumors.


The most conclusive diagnostic procedure for desmoid tumor is a biopsy (a tissue sample from the tumor taken through a simple surgical procedure).

Electron microscopy may be performed in addition to the biopsy for obtaining further clarity and confirmation for the diagnosis.

Additionally, immunohistochemical stains can be done looking for nuclear accumulation of beta-catenin, a protein that is affected by the genetic mutations often found in desmoid tumors. Nuclear reactivity shows relatively high specificity, detected in up to 90% of desmoids, regardless of site.

Antibodies are often examined in desmoid tumors, including smooth muscle actin, desmin and KIT, to aid in distinguishing them from other tumors.


The current methods of treating aggressive fibromatosis usually involve

  • Surgical removal of the tumour
  • Radiation to kill any remaining tumour cells
  • Chemotherapy 
  • Treatments with hormones or a drug called Tamoxifen may also be used
  • Monitoring – After surgery, MRI may be useful for monitoring recurrence
  • Novel molecular-targeted therapies: Kinases are regulators of cell growth, differentiation, and motility
  • Watchful waiting policy


  • NIH