A Case of Surgical Treatment for Mixed Adenoneuroendocrine Carcinoma of the Ampulla of Vater

A 56-year-old woman was referred to our hospital because of epigastric discomfort and jaundice. Contrast-enhanced computed tomography and gastrointestinal endoscopy revealed an ampullary tumor. A biopsy specimen showed adenocarcinoma of the ampulla of Vater. The carbohydrate antigen (CA19-9) level was elevated, but insulin and glucagon levels were in the normal range. Based on a diagnosis of adenocarcinoma of the ampulla of Vater, we performed subtotal stomach-preserving pancreatoduodenectomy with regional lymph node dissection. Postoperative histopathological examinations indicated both neuroendocrine carcinoma (40%) and adenocarcinoma (60%) components in the ampulla of Vater and regional lymph node metastasis. According to the 2010 WHO Classification of Tumours of the Digestive System, the diagnosis of mixed adenoneuroendocrine carcinoma (MANEC) of the ampulla of Vater was confirmed. The patient was treated for 6 months with oral administration of TS-1 as adjuvant chemotherapy. Currently, the patient is alive without recurrence 8 months after surgery. MANEC of the ampulla of Vater is rare. It is a highly malignant tumor, and the standardization of its treatment, including surgery, chemotherapy, and radiotherapy requires further study.