Although pancreatoduodenectomy is the standard treatment for periampullary neoplasms, limited pancreas-preserving resections are sometimes performed. This report describes a carcinoid tumor of the ampulla of Vater for which pancreatoduodenectomy was not feasible because of diffuse cavernous transformation of the portal vein (PV) secondary to main PV obliteration of unknown cause. We performed retroduodenal resection of the ampullary carcinoid with total preservation of the pancreas. The duodenal wall defect was primarily repaired, and the pancreatic and bile ducts were separately reconstructed using Roux-en-Y pancreaticojejunostomy and choledochojejunostomy. The patient recovered uneventfully and is currently progressing well at 10 months postoperatively, with no tumor recurrence or complications. The surgical procedures are described, and the literature pertaining to this limited surgery is reviewed.