Aggressive fibromatosis is a rare type of non-malignant tumour. Aggressive fibromatosis is also known as a 'desmoid'
tumour. Some forms of fibromatosis can be locally aggressive (fast-growing and difficult to get rid of).
Well..... sort of. The World Health Organization classifies desmoid tumours as somewhere in between truly benign
tumours and the malignant tumours. Desmoids are not truly benign because they are locally aggressive, but they do not metastasize
like malignant cancers. The bottom line is that whatever you call them, desmoids can behave like cancer.
Reviews of cases of aggressive fibromatosis have found 5-year survival rates are over 90%. People with desmoid
tumours rarely die from the tumours themselves. In a group of studies with a total of 424 patients, there were only
5 reported tumour deaths.
However, major surgery can be required to treat this form of tumour, depending on its size and location when it is diagnosed.
Surgery, radiation and chemotherapy also have their own risks and chances of complications developing. Tumours growing
on vital structures such as major blood vessels, organs, major nerves or the brain will be more difficult to treat without
risking damage to surrounding tissues. Rarely, if a tumour does not respond to other treatment methods, amputation of
the affected limb may be the only way to stop tumour growth.
Is this a malignant tumour?
No, there is no evidence of metastasis (i.e., tumour cells do not migrate
and start new tumours elsewhere in the body).
How rare is aggressive fibromatosis?
Aggressive fibromatosis has been estimated as making up 0.03% of all tumours.
What causes aggressive fibromatosis?
Causes of this tumour are still under investigation. In some forms, they appear to be inherited as several family members may be diagnosed with them. Some tumours develop in surgical scars after surgery. Desmoid
tumours may also develop in association with pregancy. Adult-onset desmoids are mostly found in women of childbearing
age, but the disease can occur in both sexes, at any age.
Researchers have discovered a number of different mutations within desmoid
tumour cells. However, what causes the mutations is not known.
Can children get this disease?
Children have been diagnosed with several types of fibromatosis, including
infantile myofibromatosis, which affects soft tissue, internal organs and bone, juvenile aponeurotic fibroma, which affects
the hands and feet, juvenile hyaline fibromatosis which affects the skin, and infantile desmoid type fibromatosis which affects
What is FAP?
FAP stands for familial adenomatous polyposis. It is a rare genetic
condition that results in hundreds of polyps forming in the colon (large intestine). Colon cancer from one or more of
those polyps is considered inevitable unless the colon is surgically removed with a colostomy. The risk of desmoid tumors
in individuals with FAP is 852 times the risk in the general population. Desmoid tumours usually develop in the abdomen
of people with FAP.
Where do desmoid tumours occur in the body?
Desmoids occur in limbs (69%) (girdle area), in the neck (19%), the trunk (12%)
or the abdomen (2%). They may also occur in the jaw, head or eye.
Is this a fast-growing tumour?
Sometimes. Some tumours grow very quickly, and others can stay the same
size for months or even years. If the tumour is very slow growing and is not causing any other problems, sometimes doctors
choose to just monitor it carefully and defer treatment.
How is aggressive fibromatosis treated?
The current methods of treating aggressive fibromatosis usually involve surgical
removal of the tumour, often followed by radiation to kill any remaining tumour cells.
Chemotherapy and treatments with hormones or a drug called Tamoxifen may also be used. Desmoid tumours are very individual
in their responses to treatment, and no one treatment alone seems to have a high success rate. What works for one person
may not work at all for another. Often, more than one treatment type is needed (i.e. surgery + radiation, or surgery
+ chemo, or chemo + radiation). If the tumour is growing on or near vital structures, your doctor may choose not to
attempt surgery but to use radiation or chemotherapy alone.
Check the 'Links' page for links to medical
articles on the treatment of desmoids.
This is not a malignant tumour - why is radiation
sometimes used to treat it?
Desmoid tumours are very prone to local recurrence - after being surgically
removed, they have a nasty tendency to grow back in the same area. Your
doctor may use radiation or chemotherapy to lower the chances of recurrence.
Will this tumour grow back?
Recurrence of desmoid tumours has been found to occur in 50% of cases, on average,
3 years after the original diagnosis. It may recur multiple times. Desmoid
tumours in the head and neck recur, on average, in 70% of cases.
Tumours can also recur after being treated with radiation. In those cases,
the tumour usually recurs at the edge of or outside of the radiation field.
I've been diagnosed with aggressive fibromatosis. What should
Discuss your treatment options with your doctor. Just make absolutely
sure that your doctor is aware how often these tumours recur, and that a follow-up schedule such as a periodic MRI is
developed so your doctor can check if your tumour is growing back. An MRI to check for recurrence may be warranted as
early as 3 months or less after surgical removal, if your tumour is particularly fast-growing. There are links to medical
articles elsewhere on this site if you or your doctor want more detailed information. You may wish to ask your doctor
to refer you to a specialist with experience in treating desmoid tumours, as the condition is rare enough that most general
practitioners never see it. In Canada, you can ask for a referral to the closest Cancer Centre.