S2202 Post-Surgical Presentation of Zollinger–Ellison Syndrome Following Resection of Endometrioid Neuroendocrine Tumor

Abstract

INTRODUCTION: Zollinger–Ellison syndrome (ZE) may present as lymph node metastases at initial presentation. Here we report a case of ZE following resection of endometrioid small cell neuroendocrine carcinoma and endometrioid adenocarcinoma. CASE DESCRIPTION/METHODS: A 76-year-old Caucasian female presented with heavy vaginal bleeding. CT scan revealed an enlarged uterus measuring 6.2 × 5.4 cm. The patient underwent uneventful laparoscopic hysterectomy with bilateral salpingo-oophorectomy and bilateral sentinel lymph node dissection. Pathological examination demonstrated stage IB mixed endometrioid adenocarcinoma and small cell neuroendocrine carcinoma. Gastrin immunostaining was negative. The patient presented three months after completing chemotherapy (one month following radiation treatment with brachytherapy) with black stool in addition to watery diarrhea for more than 6 months. The patient denied taking aspirin or nonsteroidal anti-inflammatory drug and was not taking a proton pump inhibitor (PPI). Esophagogastroduodenoscopy (EGD) demonstrated multiple non-bleeding superficial gastric ulcers with clean ulcer bases (Forrest Class III) in the antrum and prepyloric region. No ulcers were identified in the duodenum. An elevated serum gastrin level (538 pg/mL) was noted the day after EGD while not on PPI therapy. Somatostatin receptor-based imaging (Ga-68 Dotatate- PET/CT) revealed avid left paraesophageal node uptake measuring 11 × 8 mm. Stool helicobacter pylori antigen test was negative. Serum calcium (9.2 mg/dL), renal function and PTH were within normal limits. After five months, follow up EGD demonstrated two persistent (2-3 mm) clean based ulcerations in the posterior gastric wall. Gastric fluid demonstrated pH of 1 despite Pantoprazole 40 mg twice a day for 4 months. Endoscopic ultrasound examination demonstrated an ill-defined 14 × 7 mm heterogenous lymph node in the region of the lymph node noted on PET scan, which was sampled by fine needle aspiration, revealing scant lymphoid tissue insufficient for pathologic diagnosis. DISCUSSION: Here the diagnosis of ZE was based on a combination of persistent gastric ulcerations in the presence of elevated serum gastrin, gastric pH < 2, and somatostatin receptor-based imaging, despite our being unable to identify a primary lesion. Our case illustrates the importance of utilizing multiple modalities in establishing a presumptive diagnosis of ZE.Figure 1.: Multiple clean based ulcers in the gastric antrum and prepyloric region.Figure 2.: Persistent clean based ulcerations in the gastric antrum.Figure 3.: Left paraesophageal node uptake (Ga-68 Dotatate- PET/CT).