Neuroendocrine tumor of the ampulla of Vater with distant cystic lymph node metastasis: a case report.

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. CASE PRESENTATION: 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.