Chronic Intractable Nausea as the Singular Presentation of Metastatic Duodenal Neuroendocrine Tumor

Abstract

Introduction: Nausea is a non-specific symptom, often dismissed by patients and doctors alike, but may be the first sign of some solemn disease process. Case presentation: A 33 year-old Caucasian woman was referred for evaluation of chronic intractable nausea of 10-month duration, associated with intermittent right upper quadrant pain. Review of systems was negative for other symptoms. The physical exam as well as lab-work including hepatic panel and amylase/lipase was unremarkable. CT abdomen revealed cholelithiasis and a multilobulated mass in the right paramedian aspect, adjacent to duodenum, closely associated with the pancreas. It was unclear if it was arising from the pancreas, duodenum, adrenal or retroperitoneal area. Endoscopic Ultrasound (EUS) revealed an 8x8cm heterogenous appearing mass arising from the duodenal wall distinct from pancreas and kidney. Fine needle aspiration (FNA) showed well-differentiated grade-1 neuroendocrine tumor (NET) positive for pan-CK, synaptophysin and chromogranin; CDX2 staining was positive confirming the gastrointestinal origin. Laparotomy confirmed the origin of mass from the second portion of duodenum and the patient successfully underwent pancreaticoduodenectomy. Histopathology of the tumor including liver metastases was consistent with well-differentiated grade-2 NET. Discussion: Neuroendocrine cells are a specialized group of cells, which are widely distributed throughout the mucosa of GI tract and secrete hormones in response to neural or chemical stimuli leading to varied clinical presentation and symptoms. The commonest presentation is abdominal pain, but may vary from nonspecific dyspepsia to GI bleeding. In our case, patient had intractable nausea, likely due to intermittent low-grade outlet obstruction from tumor growing in the duodenal wall. Conventional imaging including CT and MRI can detect NETs but may fail to reliably demonstrate the primary organ. In such scenarios, EUS can accurately detect the tissue of origin. EUS in addition to obtaining histology serves well in the loco-regional staging. Histologically, they stained positive for Chromogranin A, synaptophysin and neuron-specific enolase.Figure 1Conclusion: This case teaches one to investigate thoughtfully such purportedly trivial complaints, to unravel unexpected findings, like NETs. EUS is an irreplaceable asset in investigation of submucosal masses and can help differentiate the tissue of origin even when cross-sectional imaging fails.Figure 2Figure 3