Pancreatic Endocrine Neoplasm Concomitant with a Complicated Endocrine History: A Case Report and Literature Review.

Background: Pancreatic neuroendocrine tumors (PNETs) are rare, and metastases when present are most commonly found in the liver or the peripancreatic lymph nodes. In this study, we present a patient who developed a metastatic PNET in the liver in the setting of multiple concomitant autoimmune disorders, including pernicious anemia and atrophic gastritis with hypergastrinemia. Case presentation: The patient is a 70-year-old woman with a history of Hashimoto's thyroiditis, thymoma, gastric carcinoid tumors, and autoimmune atrophic gastritis with pernicious anemia. She was found to have a 2 cm mass in the pancreaticoduodenal groove originating from the pancreas. A preoperative endoscopic ultrasound with fine-needle aspiration showed a well-differentiated PNET. During surgery, she was found to have multiple subcentimeter liver lesions, which on frozen section were shown to be a metastatic neuroendocrine tumor. After surgical resection, final pathology revealed a PNET with metastases to the liver. The metastatic lesions stained positive for gastrin. Conclusion: We were only able to find one other example in the literature of a PNET occurring in association with pernicious anemia. Our patient developed a metastatic PNET in the setting of multiple autoimmune disorders, including pernicious anemia.