Diagnosis and Treatment of Sporadic and Familial Adenomatous Polyposis (FAP) - Associated Desmoid Tumors: Literature Review.

Desmoid tumors account for 3% of all soft tissue tumors and 0.03% of all neoplasms. In some cases, they appear as part of various syndromes, such as familial adenomatous polyposis (FAP). Desmoids are associated with CTNNB1and APC mutations, which exclude each other. Desmoid tumors appear as slowly growing masses that often do not cause symptoms. The natural course of desmoids varies and is unpredictable. Most patients feel relieved by the benign diagnosis and underestimate the aggressive behavior of the disease.Various imaging techniques have been used for diagnosis and monitoring of desmoids, including ultrasound (U/S), magnetic resonance imaging (MRI), computed tomography (CT) scan, positron emission tomography (PET) scan and plain X-ray. The definitive diagnosis requires biopsy.Desmoids usually express β-catenin and vimentin. Sporadic tumors are associated with CTNNB1 mutation of β-catenin. If this mutation is identified, the presence of any syndrome can be excluded. FAP is inherited in an autosomal dominant fashion and is caused by a mutation of the APC gene; 10-15% of patients with FAP develop desmoid tumors while 7.5-16% of desmoids are a manifestation of FAP.The basic therapeutic approaches are surgical excision, radiotherapy and medical treatment with anti-estrogen, nonsteroid anti-inflammatory drugs (NSAIDs), cytotoxic chemotherapy and molecular therapies. Close observation of the disease progress is imperative, whether the "wait and watch" strategy has been chosen or a specific treatment has been applied. Imaging, preferably MRI, should be performed every 3 months for the first year after diagnosis, every 6 months for the second year and annually thereafter. [ABSTRACT FROM AUTHOR]