Background: Familial adenomatous polyposis is an autosomal dominant disease. It is characterized by hundreds of adenomas of the colorectal region and desmoid tumors can sometimes occur in
extracolonic manifestation of this disease.Case Report: A case of huge intraabdominal desmoid tumor invading the whole small bowel mesentery and the aorta was described. Total proctocolectomy and ileo-anal anastomosis was performed in a 42 years old woman with familial adenomatous polyposis. A huge desmoid tumor occured five years after the surgery. The tumor was 10 to 15 cm in size and multipl lymph nodes were present around it. It was originating from the mesentery of the small bowel and tightly adherent to the aorta. The frozen section of the tumor revelaed mesenchymal tumor. Estrogen receptor was positive.But the mass was considered unresectable unless the removal of the whole small intestine and the excision of the aorta were performed. vealed mesenteric fibromatosis. The patient was discharged on 4th postoperative day and then tamoxifen (20 mg daily) was prescibed. She was followed up by clinical and CT examinations. Neither clinical nor CT evidence of disease progression has been observed for eighteen months.Conclusions: This case was considered us that the progression of the desmoid tumor is affected by the hormonal influence.

Keywords: Familial adenomatous polyposis, total proctocolectomy, desmoid tumor