Aggressive fibromatosis in children: a changing approach

Desmoid tumor, also known as aggressive fibromatosis (AF), is a rare monoclonal, fibroblastic proliferation arising in musculoaponeurotic structures. AF is a tumor of intermediate malignancy, with a strong potential for local invasiveness and recurrence. The treatment of choice for these tumors has been changing all the time and may involve surgery, radiotherapy and/or systemic approaches. Surgery generally used to be considered the mainstay of treatment for AF, its goal preferably being a microscopically complete resection with histologically free margins. Mutilating surgery or procedures causing significant loss of function and/or chronic symptoms should be avoided. Involvement of surgical margins is probably associated with an increased risk of local recurrence. Postoperative radiotherapy could be used in cases with positive margins after surgery, or to avoid mutilating surgery in cases of inoperable or inaccessible disease. Postoperative radiotherapy has been reported to raise local disease control to a level similar to that of complete resection, but is associated with a relatively high rate of complications. Systemic treatment may be indicated in case of locally-advanced disease. Several risk factors for local recurrence have been investigated and include: young age, large size, presentation as recurrence, girdles or intra-abdominal location, involved surgical margins, and β-catenin-activating mutations. Recently collected data prompted the suggestion that these tumors warrant a wait-and-see strategy (clinical-radiological observation, without any treatment), since their natural history is often characterized by lengthy periods of stability or even regression, considering to treat only patients with progressing or symptomatic disease.