S4531 Rethinking Biopsy in Gastric Ulcers: A Rare Aggressive Neuroendocrine Tumor Initially Overlooked

Introduction: Gastric ulcers are frequently attributed to non-steroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori infection, with malignancy being an uncommon but critical etiology. Endoscopic features guide risk stratification: malignant ulcers often display irregular, thickened margins and nodular or fused folds, whereas benign ulcers are characterized by smooth, regular edges and a flat base. Current guidelines recommend biopsying ulcers with malignant features or those in high-risk patients, but no consensus exists for reassuring-appearing ulcers in low-risk individuals. Case Description/Methods: A 52-year-old woman with chronic nonsteroidal anti-inflammatory drug use for osteoarthritis, hypertension, and obesity presented with several weeks of abdominal pain and melena, culminating in hematemesis. Laboratory evaluation revealed acute anemia (hemoglobin 7.5 g/dL). Initial esophagogastroduodenoscopy (EGD) demonstrated a 1.5 cm gastric cardia ulcer with a visible vessel that bled upon manipulation; hemostasis was achieved with epinephrine injection, bipolar cautery, and clipping. The ulcer appeared benign, and no biopsy was obtained. Four weeks later, the patient returned with recurrent symptoms; abdominal computed tomography revealed an 11.2 × 10.4 × 11.6 cm left upper quadrant mass. Repeat EGD showed 2 cratered ulcers at the prior site, prompting biopsy. Histopathology identified small cell carcinoma. Subsequent positron emission tomography-computed tomography and brain magnetic resonance imaging excluded extra-abdominal primary or metastatic disease. A diagnosis of primary gastric neuroendocrine carcinoma was established, and systemic chemotherapy was initiated. Discussion: This case highlights the limitations of endoscopic appearance and traditional risk stratification in detecting rare, aggressive malignancies. We advocate for a low threshold to biopsy all gastric ulcers—even those appearing benign in low-risk patients—to facilitate earlier diagnosis and improve clinical outcomes.