A 20 year-old man presented with a large desmoid tumor involving the mesenteric root associated with obstruction and fistulas between the tumor and the small bowel, requiring prolonged nasogastric decompression and parenteral nutrition. A laparotomy was attempted at another hospital, but aborted due to mesenteric involvement. We offered ex vivo resection of the tumor and intestinal autotransplantation. After entering the abdomen, the viscera were mobilized off the retroperitoneum, revealing the large mesenteric tumor. The transverse colon was then transected. Due to a fistula between the duodenum and tumor as well as pancreatic head involvement, a pancreaticoduodenectomy was added to the procedure. A cholecystectomy was performed, followed by the ligation of the GDA. The distal stomach was then transected, followed by transection of the pancreas. Once all of the involved viscera were mobilized, the SMV and SMA were ligated and the specimen flushed with cold preservation solution. The tumor was then resected off the mesenteric vessels in the back table. The remaining 400cm of small bowel were then reimplanted and reperfused via the SMV and SMA. The gastrointestinal reconstruction included a gastrojejunostomy, roux-en-y choledochojejunostomy, pancreaticogastrostomy, and end colostomy. The patient recovered well and was tolerating enteral nutrition one week following surgery. He was discharged after two weeks, and returned three months later for a colostomy reversal.