Operation and abdominal desmoid tumors in familial adenomatous polyposis.

Abdominal desmoid tumors (ADT) have become an important problem because of the increased survival of patients with familial adenomatous polyposis (FAP). Of 240 patients operated upon for FAP between 1978 and 1991, 29 (16 men and 13 women) had ADT. Diagnosis was made at laparotomy in 19 patients, while an abdominal mass or intestinal obstruction was the principal cause of discovery in the ten remaining patients. Twenty ADT were discovered after a previous laparotomy performed an average of three years earlier. Nine ADT occurred in 146 patients who had previously undergone a coloproctectomy and ileal pouch-anal anastomosis and eight occurred in 74 patients who had abdominal colectomy and ileorectal anastomosis. Desmoid tumors were responsible for eight instances of intestinal obstruction and one instance of small intestinal perforation. One death was directly related to ADT. In four of nine patients, ADT was responsible for a deterioration of the functional results of ileoanal anastomosis, but pouch removal was not necessary. Conversion of ileorectal anastomosis to ileoanal anastomosis and excision of carcinomas that occur in the residual rectum after ileorectal anastomosis were impossible because of ADT in three and two patients, respectively. Complete surgical removal of the tumor was possible in seven patients only and four patients had a recurrence. None of the medical therapies used (sulindac, tamoxifen and chemotherapy) were effective. The results of this study confirm the high incidence, severity and absence of effective treatment of ADT in FAP. Desmoid tumors occurring after ileorectal anastomosis seem to be more severe than after ileoanal anastomosis because, in the former instance, they may interfere with the further management of the rectal stump.