Gastric adenocarcinoma at stage IV with complete remission after neoadjuvant therapy concurrent with adenosquamous carcinoma of the ampulla of Vater: a case report and literature review

BACKGROUND: Adenosquamous carcinoma (ASC) of the ampulla of Vater (AmV) is exceedingly rare with more aggressive behavior and worse prognosis than adenocarcinoma. The finding of ASC at the AmV in combination to the gastric adenocarcinoma has never been reported in the literature before. CASE PRESENTATION: An old lady was diagnosed as gastric adenocarcinoma at stage IV with enlargement of supraclavicular lymph nodes by gastroscopy and histopathological evaluation 3 years ago. Afterwards, the patient achieved complete remission after regular chemotherapy. However, the patient manifested yellow sclera and skin, choluria and clay colored stool 3 months ago. Preoperative contrast-enhanced CT, ERCP, MRCP, and PET/CT revealed the presence of an ampullary tumor. The patient then underwent laparoscopic radical gastrectomy and pancreaticoduodenectomy with regional lymph node dissection. Postoperative cytological analyses confirmed the diagnosis of gastric ulcer with complete response to neoadjuvant therapy and ASC at the AmV. The patient’s postoperative outcome was uneventful. CONCLUSION: Drawing firm conclusions about the diagnosis of ampullary ASC is difficult because of the difficulty in acquiring both adenocarcinoma and SCC components by fine needle biopsy. The rarity of ASC of the AmV coexistent with gastric carcinoma makes it difficult to elucidate their clinicopathological characteristics, therapeutic strategies and overall prognosis. Surgical resection still remains the main treatment method.