What are the most common causes of desmoid tumors?

FAP and pregnancy: The exact cause of desmoid tumors is unknown but they appear intrabdominally in about 20-30% of people who have a genetic condition called fap (familial adenomatous polyposis). Sporadically, they can occur in the abdominal wall or extremities during or following pregnancy or sometimes following trauma or surgery. These tumors rarely spread but can be locally aggressive causing pain or obstruction.

Trauma: Most desmoids arise in the reionof the abdominal wall. Low grade frequent trauma to the abdomen can cause the lesion. Extra abdominal desmoids can also arise on the extremities . All respond to resection and if large, anti estrogen.