title: Neuroendocrine tumor of the ampulla of Vater with distant cystic lymph node metastasis: a case report.
abstract: BACKGROUND
  Neuroendocrine tumors (NETs) of the ampulla of Vater are rare and difficult to diagnose. We report a rare case of a small NET of the ampulla of Vater with metastasis to distant lymph nodes.
  
  
  METHODS
  The patient was a 54-year-old man complaining of epigastric pain and melena. Upper gastrointestinal endoscopy revealed a bulging papilla with active bleeding, which was diagnosed as a well-differentiated NET of the ampulla of Vater. An approximately 10-mm hypervascular tumor at the ampulla of Vater and a 41-mm cyst adjacent to the wall of the jejunum were revealed by abdominal computed tomography. We performed pylorus-preserving pancreaticoduodenectomy with lymph node dissection. Macroscopic examination revealed a 9-mm tumor of the ampulla of Vater and a 52-mm cyst adjacent to the wall of the jejunum. Histological examination revealed that the cyst was a lymph node metastasis. The final diagnosis was non-functional NET G1 of the ampulla of Vater, designated T1N1M0 stage IIIB. Postoperatively, the patient underwent no treatment and has had no recurrence for 4 years.
  
  
  CONCLUSIONS
  This case demonstrates that sporadic NETs of Vater's papilla have aggressive metastatic potential even with a small primary lesion, and radical resection with lymphadenectomy is recommended for all cases.
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.|Department of Surgery and Laparoscopic Surgery, Gunma Prefecture Saiseikai-Maebashi Hospital, 564-1 Kamishinden-machi, Maebashi, Gunma, 371-0821, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Tsukagoshi
authors.affiliation: Department of Surgery and Laparoscopic Surgery, Gunma Prefecture Saiseikai-Maebashi Hospital, 564-1 Kamishinden-machi, Maebashi, Gunma, 371-0821, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hosouchi
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan. karaki@gunma-u.ac.jp.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Araki
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Mochida
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.|Department of Surgery and Laparoscopic Surgery, Gunma Prefecture Saiseikai-Maebashi Hospital, 564-1 Kamishinden-machi, Maebashi, Gunma, 371-0821, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Aihara
authors.affiliation: Department of Hepatobiliary and Pancreatic Surgery, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Shirabe
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwano
keywords: Ampulla of Vater; Lymph node metastases; Neuroendocrine tumor; Surgical resection