A 65-year-old female was seen at the hospital because of epigastralgia and nausea. The patient had been followed up after undergoing laparoscopically assisted sigmoidectomy for sigmoid carcinoma at another hospital in August 1997. A follow-up CT scan revealed a tumor with 4cm in size, growing outside of the duodenum. But the patient denied more close examinations. Three years later, since she had nausea, dynamic CT scan was performed. The tumor had increased to be 8cm in size and there was bleeding inside of the tumor. After her symptoms disappeared with conservative therapy, she was referred to our hospital for operation. At that time, the tumor reduced to 4cm in size, and the duodenal mucosa was normal on gastroenterological fiberscopy. Perioperative diagnosis of carcinoid was made by cytology guided by endscopic ultrasonograpy of the submucosal cells. We performed pancreaticoduodenectomy with lymph node dissection in December 2008. Histopathology disclosed that tumors 7 mm and 5 mm in size which could not be identified before operation were found to be carcinoid tumors and that the 4×3×2.5 cm extramurally growing tumor of the duodenum which was diagnosed as carcinoid preoperatively was clarified to be lymph node metastasis of the carcinoid tumors. In this paper, we report a rare case of small carcinoid tumors of the duodenum, in which we could follow the solitary metastatic lymph node for four years. In a review of the literature, carcinoid tumors smaller than 10mm in size with a huge lymph node metastasis are very rare.