Gastroenteropancreatic Neuroendocrine Tumors: A Case Series

INTRODUCTION: Neuroendocrine tumors (NETs) are rare tumors that originate from neuroendocrine cells. Over 60% of NETs originate in the GI tract, with the small and large intestines being the most common sites of diagnosis. Herein we review 3 cases of GEP NETs diagnosed via histopathology at Houston Gastro Institute from 2017-2019. CASE DESCRIPTION/METHODS: CASE 1: A 30-year-old female who presented with 4 days of epigastric abdominal pain. Workup at that time including CBC, CMP, amylase, lipase, and helicobacter pylori was unremarkable. She was lost to follow up for a year and then presented to the emergency room with abdominal distension and severe right upper quadrant pain radiating to the back. Abdominal Ultrasonography revealed small nodules scattered throughout the liver. Transjugular biopsies of the liver masses revealed metastatic neuroendocrine tumors in portal tracts and sinusoids with positive nuclear staining for CDX-2 consistent with gastrointestinal primary tumor. NetSpot PET CT scan Ga 68-dotatate revealed extensive hepatic and lymph node metastasis, but a definite primary lesion could not be localized. CASE 2 A 67-year-old female who presented with constipation and rectal bleeding. Colonoscopy showed an infiltrative and ulcerated bleeding 12mm mass in the anal canal. Multiple cold forceps biopsies were performed which revealed synaptophysin positive tumor cells consistent with high-grade neuroendocrine carcinoma of small cell type. She underwent tumor resection, radiation therapy, and chemoradiation with carboplatin and etoposide. CASE 3: A 54-Year-old female who presented with 4 months history of diarrhea with 2-3 loose stools daily. Abdominal CT revealed 2cm enhancing mass in the pancreatic body. MRI showed arterial enhancement of pancreatic tail mass measuring 2.3 × 1.7cm. Biopsies via EUS confirmed well-differentiated nonfunctioning low-grade neuroendocrine tumor. NetSpot PET CT scan Ga 68-dotatate revealed a primary pancreatic neuroendocrine malignancy without evidence of metastasis. She was referred to surgical oncology for laparoscopic pancreatectomy. DISCUSSION: These cases exemplify the challenges in establishing the diagnosis of GEP NETs. Although these tumors are rare and usually slow-growing, they have a vast range of clinical presentations that make them difficult to diagnose and treat. Despite the rarity of these tumors, consideration of NETs as a differential diagnosis is necessary for early diagnosis, treatment, and survival.