Snapshot A 35-year-old man presents to his primary care physician after noticing a mass in his mid-abdomen. He denies any recent trauma to the abdomen, nausea, vomiting, or changes in his bowel habits. He says that the mass is not painful but causes mild abdominal disomfort. His father had "colon polyps" that required prophylactic removal of his colon. On physical examination, there is a firm and oblong mass in the epigastric region that is not painful to palpation. An MRI of the abdomen demonstrates an intraabdominal mass. He undergoes surgical removal, and pathology demonstrates spindle cells with abundant fibrous stroma that is concerning for a desmoid tumor. Introduction Overview slow growing, locally aggressive fibroblastic tumors associated with a high rate of recurrence despite complete resection have no metastatic potential Epidemiology Incidence rare (0.03% of all neoplasms) Location trunk/extremity abdominal wall intraabdominal (e.g., bowel and mesetary) predominate in familial adenomatous polyposis Risk factors familial adenomatous polyposis Gardner syndrome high estrogen states (e.g., pregnancy) antecedent trauma ETIOLOGY Pathophysiology pathobiology APC gene and beta-catenin appear to be involved Genetics mutations Wnt signaling is thought to play a role Associated conditions familial adenomatous polyposis Gardner syndorme pregnancy Presentation Symptoms common symptoms painless or minimally painful mass intestinal obstruction nausea and vomiting bowel ischemia abdominal pain Physical exam desmoid tumors can occur at any body site mass on abdominal palpation nontender to palpation breast mass in breast demoids (rare) Imaging Cross-sectional imaging with CT or MRI indications to visualze the mass affecting a designated part of the body findings desmoids do not have a charateristic imaging fings and are hard to distinguish from malignant soft tissue tumors Studies Invasive studies histology performed with incisional viopsy obtains much more tissue than a core needle biopsy findings monoclonal fibroblastic prolierations spindle cells with abundant fibrous stroma Differential Keloids differentiating factors painful and pruritic does not spontaneously regress Treatment Nonoperative observation indication asymptomatic patients who can be reliably followed radiation therapy indications patients who are not surgical candidates patients who refuse surgery in patients with significant surgical morbidity after resection Operative complete surgical excision indication resectable extraabdominal or abdominal wall desmoids Complications Death if desmoid tumor grows in vital structures and organs (e.g., bowel), it can directly compression or disrupt of the organ function Prognosis Natural history of disease variable, most progressively grow overtime and may have growth arrest or spontaneously regress Prognostic variable familial adenomatous polyposis desmoid tumors tend to recur at surgical sites infiltration to vital organs can result in death even though it is histologically benign