What is a desmoid tumor?
A desmoid tumor is an uncommon bland fibrous neoplasm that may arise sporadically or in association with familial adenomatous polyposis (FAP). Patients with FAP are at a thousand-fold increased risk of developing intraabdominal desmoid tumors, and patients who have had prior abdominal surgery are at increased risk for abdominal wall desmoid tumors. Sporadic intraabdominal desmoid tumors are more common in women, are solitary in >90% of cases, tend to be larger in size, and predominantly affect the pelvis and retroperitoneum. FAP-associated intraabdominal desmoid tumors are equally common in men and women, are multiple in 40% of cases, tend to be smaller in size, and predominantly affect the small bowel mesentery.