S3686 A Rare Case of Duodenal Neuroendocrine Tumor

Abstract

Introduction: Neuroendocrine tumors of the duodenum (D-NET) are rarely seen constituting less than 2-3% of gastrointestinal tumors. With NET on rising, it is important to recognize this rare tumor and treat it with early surgical or endoscopic resection. Case Description/Methods: A 52-year-old white male was seen in the office for new onset of dysphagia worse with solid food for few months. He had a history of squamous cell carcinoma of the tongue and had undergone surgical resection with concurrent chemotherapy with cisplatin. His examination and laboratory findings were unremarkable. On endoscopic examination, the patient was found to have a 5 mm size nodule in the second part of the duodenum which was removed with a cold biopsy (Figure A&B). The histopathologic findings were consistent with a well-differentiated neuroendocrine tumor (NET) (figure C&D). The tumor cells were strongly positive for synaptophysin (figure-D), CD56, chromogranin and showed < 1% of Ki-67 labeling index supporting the diagnosis of NET. A PET/CT- GA-68 Dotatate scan confirmed no residual tumor but an increased uptake in the lymph nodes above and below the diaphragm was noted (figure E). These lymphadenopathies are likely falsely positive given the symmetric uptake with awaiting biopsy on follow up. Three months later a repeat endoscopy with biopsy of previous polypectomy site did not show any evidence of remnant NET. Oncology was consulted with suspected disseminated NET and is awaiting further investigation. Discussion: NET is a type of epithelial tumor with predominant neuroendocrine differentiation arising from various organs of the body. The majority of these cases arise from the gastrointestinal tracts followed by lungs, pancreas, ovaries, and head & neck region. Although the GI tract is the most common site of occurrence the NET-D are very rarely seen, constituting less than 3% of GI NET. The overall rate of the NET is on rising with an annual rate of 6.3%. This rise to some extent can be attributed to increased diagnostic imaging utilization. D-NETs produce symptoms based on their location resulting in abdominal pain, intestinal obstruction, jaundice, or rarely pancreatitis. By the virtue of their hormonal production, they can lead to flushing, diarrhea, skin rashes, nausea, or peptic ulcer disease. It is important to recognize these rare tumors and treat them either with surgical or endoscopic resection.Figure 1:: Figure A& B: Esophagogastroduodenoscopy (EGD) – A 5 mm size nodule seen in the second part of the duodenum with normal covering mucosa removed with cold biopsy. Figure C: Duodenal nodule on biopsy (H & E stain @ 4X) - The nested appearance of monomorphic population of tumor cells without nucleoli, necrosis or brisk mitotic activity consistent with neuroendocrine tumor. Figure D: Duodenal nodule on biopsy (4X)- Synaptophysin Immunohistochemical Stain positive consistent with neuroendocrine tumor. Figure E: PET/CT- GA-68 Dotatate: No duodenal uptake noted. Multiple radiotracer acid lymph nodes above and below the diaphragm with prominent on the axilla and bilateral iliac chain & inguinal region.