Some of these reasons are known, and some of these reasons are unknown. Even though desmoids are associated with many different conditions, they are prevalent with Gardner's Syndrome patients.
Desmoid tumors are something to watch for after surgery with FAP patients.
A few years ago, it was generally accepted that these tumors needed to be removed surgically. At a time when surgery seemed to be the only option, using chemicals to shrink these tumors was considered an experimental alternative to inoperable desmoids. But now there is evidence to support an opinion that surgery actually increases the chance of new desmoids, and chemical treatment is being used as an option, regardless of operability. Each case needs to be reviewed as to treatment options. There are no generalities that apply to all desmoids.