A 41-year-old female was admitted into Nan Fang Hospital for severe abdominal pain with bloody-mucoid stool for a month. The symptoms started a year ago without obvious causes and she did not have any systemic treatment. The patient felt fatigue and loss of weight for the last three months and increased frequency of bloody-mucoid discharge from 2-4 times/day to 10 times/day for the last month. Two weeks ago the patient had a proctoscope with biopsy in Pan Yu people's Hospital. The pathological diagnosis was rectal villous adenoma with focal malignant changes. Rectal examination in this hospital found a rectal mass, 4 cm from the anus, longitudinal growing and occupying a quarter of the circumference. Further colonofiberscope diagnosis was familial polyposis of colon. Family history showed that her father died of lung cancer, her mother died of colonic cancer and her brother and sister were healthy. A total colo-rectectomy with ileostomy was performed.