Ref: Sabiston Textbook of Surgery, 19th edition, Page 1095Explanation:"Desmoid tumours are commonly associated with familial adenomatous polyposis (FAPi in which colonic polyps are the most common feature. "Ref: SabistonDESMOID TUMOURDesmoid tumor, also known as fibromatosis or aggressive fibromatosis.It is an uncommon neoplasm that occurs sporadically or as pail of an inherited syndrome associated with:o Familial adenomatous polyposis (FAP). o Gardner's syndrome, an autosomal dominant syndrome of GI adenomatous polyps or adenocarcinoma, osteomas, and skin and soft tissue tumors.PathophysiologyArise from fibroaponeurotic tissue.Lack metastatic potential.Locally aggressive and invasive, with a high propensity for recurrence.Associated with oral contraceptive use.Estrogen receptors.ClassificationDesmoid tumors are typically classified by location:Extra-abdominal or extremity desmoids (i.e., those tumors occurring in the proximal extremities or limb girdle).Abdominal wall tumors.Intra-abdominal desmoids, which involve the mesentery, pelvis, or bowel wall.Clinical FeaturesMajority of desmoid tumors are sporadic.Typically in young women during pregnancy or within a year of childbirth.Typically present as a slowly growing mass.Usually present with an asymptomatic mass or with symptoms related to mass effect from the tumor.Often a temporal association between the discovery of the tumor and an antecedent history of abdominal trauma or operation.InvestigationsImaging (CT or MRI) is necessary to delineate the extent of tumor involvement fully.No need to perform staging for metastatic disease.Biopsy is required to establish the diagnosis.Core needle biopsy or incisional biopsy will demonstrate a tumor composed of bundles of spindle cells and an abundant fibrous stroma.Immunohistochemistry can help clarify difficult diagnoses.Typically stain positive for b-catenin, actin, and vimentin and stain negative for cytokeratin and S-100.ManagementSurgerySurgery is the treatment of choice.Resection of the tumor with a wide margin of normal tissue is the optimal treatment.Often, the extent of this resection will require abdominal wall reconstruction with local tissue Haps or mesh prostheses.RadiationAbdominal wall desmoids are responsive to radiation therapy, although the treatment effect is slow and may be progressive over several years.Radiotherapy as Primary TreatmentRadiotherapy alone is an acceptable treatment option for patients w ith unresectahle desmoid tumors or minors for which resection will he associated with high morbidity risks or major functional loss.Adjuvant RadiotherapyAd juvanl radial ion therapy is controversial, with most centers reserv ing this modality for patients with positive margins, or close margins.Neoadjuvant RadiotherapyThe use of neoadjuvant radiation therapy is less v ell accepted than adjuvant radiation therapy because of the slow response times, often 1 year or more, with the potential for making subsequent abdominal wall reconstruction more difficult, and few studies demonstrating a clear benefit.Adjuvant Medical TherapyTamoxifen.NSA1DS particularly Indomethacin and Sulindac.Imatinih A tyrosine kinase inhibitor.Chemotherapy- Methotrexate with vinblastine, doxorubicin-based therapy, and ifosfamide- hased regimens.For desmoids with rapid growth, medical oncologists may recommend therapies typically used for sarcomas, such as doxorubicin and dacarbazine.