A Case of Functional, Multifocal Duodenal-pancreatic Neuroendocrine Tumors

Abstract

Introduction: Gastroenteropancreatic neuroendocrine tumors are rare neoplasms that are typically solitary and non-functional. We present a case of functional, multifocal duodenal-pancreatic neuroendocrine tumors. Case Presentation: A 57 year old male presented with a three week history of severe, colicky abdominal pain unrelated to eating. He also reported a 100 pound, intentional weight loss. Medical history was notable for new onset diabetes. He denied alcohol or tobacco use. There was no family history of pancreatic cancer or pancreatitis. Prior workup included an abnormal HIDA and an EGD with only gastritis. He underwent a laparoscopic cholecystectomy, without improvement in symptoms. Because of his weight loss and new diabetes, an MRI/MRCP was done showing an atrophic pancreas with scattered cysts. EUS guided aspiration of a large 11.2 by 11.5mm cyst in the pancreatic tail revealed a solid component. Subsequent FNA demonstrated cells consistent with a pancreatic neuroendocrine tumor (PNET). Follow up endocrine studies revealed significantly elevated gastrin, undetectable gastrin secreting peptide, and mildly elevated glucagon and C peptide levels. Other studies were within normal range. The patient underwent a distal pancreatectomy with histology showing a well-differentiated neuroendocrine neoplasm and focal IPMN. Peripancreatic lymph nodes were negative. Patient initially did well postoperatively, but developed recurrent symptoms. Repeat EGD with EUS identified a 2cm mass at the duodenal bulb. Interval CT also demonstrated development of small, scattered lesions in the liver, left adrenal and lung bases. The patient was subsequently diagnosed with multifocal duodenal and pancreatic neuroendocrine tumors. Discussion: This patient was initially thought to have a cystic pancreatic neuroendocrine tumor; however, he was subsequently found to have multiple tumor foci, which is more consistent with MEN1 Syndrome. In this case, glucagon levels were elevated, explaining his symptoms of new onset diabetes and abdominal pain. His gastrin level was also elevated, however interpretation of this was complicated by concurrent PPI use. Because of the potential for multiple primary lesions, when an EUS is performed for evaluation of a possible cystic PNET, a full EGD should also be considered. Treatment for MEN1 is challenging in part because tumors are usually multiple, precluding surgical resection. Thus, treatment is geared toward a medical approach.