Desmoid Tumors

Desmoid tumors arise from connective tissue - the cells involved with the formation of muscle, fibrous and nerve tissue. Desmoid tumors, also called aggressive fibromatoses , are locally aggressive. This means that they can grow into and even destroy adjacent normal tissues, even bones. They do not, however, have the capacity to spread distantly (metastasize) throughout the body. Hence, most doctors consider desmoid tumors to be benign and not malignant. But regardless of the name, tumor-related destruction of vital structures and/or organs can be fatal. 

Desmoid tumors are uncommon. The estimated incidence in the general population is 2-4 per million people per year. In the United States, this would represent approximately 900 new tumors annually. The numbers are likely to be far greater because of the lack of recognition of the type of tumor by pathologists and the various terminologies used to describe it . Because of inconsistent and inaccurate reporting procedures, accurate statistics about the number of desmoid tumor cases have not been kept.

Individuals between the ages of 15 and 60 are most often affected. Desmoids are rare in the young and in the elderly. They are slightly more common in women than in men, and there is no significant racial or ethnic distribution.
Desmoid tumors may occur sporadically, or in association with familial adenomatous polyposis (FAP) (a genetic abnormality). The combination of familial polyposis and desmoid tumors, along with other non-intestinal manifestations, has been referred to as Gardner’s syndrome. The term Gardner’s syndrome is not used as frequently as in the past, because it is now recognized that patients with familial polyposis with or without desmoid tumors may have the same genetic abnormality – thus, there is not a separate “syndrome” just for people with polyposis and desmoids.