Management of desmoid tumors associated with familial adenomatous polyposis: a three-decade experience of a tertiary center in Brazil.

Background: Aggressive fibromatosis, also known as desmoid tumor (DT), is a locally aggressive myofibroblastic neoplasm originating from deep soft tissues, characterized by an infiltrative growth pattern with a tendency for local recurrence. DTs account for 0.03% of all neoplasms, and cases associated with familial adenomatous polyposis (FAP) account for 5-15% of DTs.

Aims: The aim of this study was to report the prevalence of DTs in patients operated on for FAP, describe the epidemiological profile, and evaluate the risk factors for tumor development, treatments performed, associated complications, and follow-up.

Methods: This retrospective study assessed the medical records of patients with FAP who underwent surgery between 1990 and 2021 and developed DTs during follow-up.

Results: In the study period, 147 patients with FAP were operated on; of these, 97 underwent total proctocolectomy with ileal-pouch anal anastomosis, 33 underwent total colectomy with ileorectal anastomosis (IRA), 14 underwent total proctocolectomy with terminal ileostomy, and three underwent total colectomy with partial proctectomy and low IRA using an ileal-pouch. A total of 26 patients (17.7%) developed DT; most were female (61.5%), were White (73.1%), and had a family history (84.6%). The most frequent complications were intestinal and ureteral obstructions. Long-term follow-up showed that six patients were free of disease, 14 were stable and undergoing drug therapy, four died due to complications of the disease, and two were lost to follow-up.

Conclusions: The prevalence of DT tumor was relatively high and more commonly observed in patients with a family history of the tumor. The disease presented high rates of morbidity and mortality.