A desmoid tumor is considered a benign tumor, but can behave aggressively. Actually, it falls just between malignant (cancer) and benign. Fortunately, a desmoid tumor does not spread. The cause may be heredity, scar tissue or hormones. It is more common in women than in men. This tumor is rare and only occurs in 1 in 350,000 people. This makes research and treatment difficult. An operation is not always useful and sometimes another additional treatment is necessary. The prognosis is therefore disappointing for many.
What is a desmoid tumor?
When we think of a tumor we immediately think of cancer or a malignant tumor. But the name tumor stands for growth. This can be benign or malignant. A desmoid tumor is a benign tumor that has a soft tissue structure. Think of tendons, muscles or connective tissue. Although this is a benign tumor, it can behave locally aggressively.
The tumor is also called a borderline tumor. This is because it is not malignant, but also not as benign as we would like. Actually, this type of tumor is somewhere in between. Other names for desmoid tumor are aggressive fibromatosis or soft tissue tumor.
Who gets it?
Anyone can get a desmoid tumor. Yet there are always groups of people who are more at risk. Most people who experience it are between 25 and 35 years old. This does not mean that this tumor cannot develop at an earlier or later age. It is rarely seen in children. And more in women than in men. By the way, this is a rare tumor. It occurs in 1 in 350,000 people. This means that there are on average 45-50 people in the Netherlands with a desmoid tumor.
Causes
One of the most common causes is hormone balance in women. Estrogen is a hormone that plays a role in the menstrual cycle and pregnancy. The ovaries produce this hormone. During pregnancy it is the placenta that produces this hormone. Sometimes this hormone causes a desmoid tumor to develop.
Scar tissue can also be a cause. A desmoid tumor can more easily form in this tissue. We also see this more often in women who have given birth by caesarean section. In addition, desmoids can form in any scar tissue. The tumor consists of fibroblast cells. A fibroblast cell is an important cell of connective tissue.
Another cause is a mutation in the APC gene or CTNNB1 gene or heredity. If there is a hereditary form of colon cancer in the family or familial adenomatous polyposis, the risk is increased.
Symptoms
A desmoid tumor can arise anywhere. It most commonly occurs on the abdominal wall, in the abdominal cavity, in the chest, limbs, neck or head. A desmoid tumor in the abdominal cavity is called intro-abdominal. When they lie outside the abdominal cavity we call them extra abdominal.
A desmoid tumor grows slowly. There is often no pain. The tumor has an infiltrating growth. This means that it grows within the surrounding environment or organs. Because the tumor presses on organs, tendons, muscles or other tissue, loss of function can occur. For example, if the tumor is located in the intestines, the intestines can move less well. Blockages can then occur, resulting in abdominal pain. With a tumor in the abdominal wall, the abdominal muscles may feel hardened.
Therapy
Treatment can be delayed. This is possible because a desmoid tumor, unlike other tumors, does not spread. In some cases, the tumor shrinks on its own. But treatment is necessary if complaints occur. Surgical removal is not always possible. The tumors grow into other tissue, making removal difficult. Sometimes it is possible to remove the tumor in its entirety, including a margin around it. The cut edges are then clean. In this case the chance of complete healing is greatest. However, in many cases this is not possible for the reason mentioned earlier. Sometimes multiple operations are required, which also causes many problems.
The tumor often returns. This can happen months to years later. This happens because tumor cells remain in surrounding tissue. These cells grow again into a new desmoid tumor. The complaints then start again. In this way, patients sometimes spend years receiving treatment.
Another treatment that sometimes achieves good results is hormone treatment. This is an anti-estrogen treatment. This suppresses the hormone estrogen. The stimulation for the growth of a desmoid tumor then disappears.
Irradiation is also a possibility. With the help of radiation, the tumor is reduced in size and in good cases destroyed. If the tumor cannot be removed in any way, chemotherapy will be started. This is a series of medicines containing synthetic substances that have a cell-killing effect. Chemotherapy is widely used for all forms of cancer, but also for benign tumors, bacterial infection, malaria and helminth infections.
Prognosis
The prognosis or what the future looks like after treatment is not entirely certain. If the tumor including the surrounding area can be removed and all tumor cells are removed, the chance of recovery is greatest. Additional hormone therapy can prevent a new tumor from growing again. But for many patients it is a long suffering that requires many operations. A desmoid tumor is in any case not fatal, but it does cause a lot of discomfort.
