A Case of Resected Mixed Acinar-neuroendocrine Carcinoma with Synchronous Liver Metastases

Abstract

A 69-year-old man presented with upper abdominal pain. Computed tomography showed a tumor located at the pancreatic head and two liver tumors suggestive of metastases. The pancreas tumor invaded the duodenum and showed tumor thrombus in the superior mesenteric vein. He was diagnosed with pancreatic neuroendocrine carcinoma based on the histopathological examination of the biopsy samples. In the course of chemotherapy with the regimen of irinotecan and cisplatin elsewhere, he visited our hospital to ask for a second opinion. Histopathological rediagnosis at our hospital revealed that the tumor was pancreatic neuroendocrine tumor grade 3 from the classification of WHO 2019. Since the Clinical Practice Guidelines for Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NEN) 2019 in Japan recommend multidisciplinary therapy including resection of neuroendocrine tumor and synchronous liver metastases, he underwent pancreaticoduodenectomy with removal of portal vein/superior mesenteric vein tumor thrombus, and two limited resections of the liver. The pathological diagnosis was mixed acinar-neuroendocrine carcinoma. He underwent adjuvant chemotherapy and has been recurrence free as of 15 months after the surgery. Our experience with the case is informative in clinical practice because clinical managements of pancreatic tumor with synchronous liver metastasis differ depending on its pathological diagnosis.