Clinical Case Summary
Gastric neuroendocrine tumors (NETs) are classified into three types based on their pathogenesis. Type 3 NETs are sporadic, not hypergastrinemia associated , and typically present as solitary, aggressive lesions with a higher metastatic potential. Current ENETS guidelines recommend surgical resection for lesions larger than 20 mm, particularly for Type 3 NETs, to minimize the risk of metastasis. We present the case of a 54-year-old male admitted for syncopal episodes and anemia (Hb 10.5 g/dL). After treatment with acetylsalicylic acid and enoxaparin for suspected myocardial ischemia, he developed a pre-syncopal event and a drop in hemoglobin to 6.8 g/dL. Urgent esophagogastroduodenoscopy (EGDS) revealed a 20 mm pedunculated polyp in the gastric body (Fig 1-2-3). Biopsies confirmed a neuroendocrine tumor (NET) with a Ki67 index of 1%. Systematic gastric mucosal mapping showed no other histological abnormalities, supporting the diagnosis of a sporadic Type 3 NET. Staging with contrast-enhanced CT, 68Gallium PET (68Ga-DOTATOC), and endoscopic ultrasound (EUS) excluded local invasion, nodal involvement, and distant metastases. Given the 0-Ip morphology according to the Paris classification, an endoscopic resection was performed using a hot snare technique with endoloop placement at the base of the peduncle. Histology confirmed a 21 mm NET G2 (Ki67 8%) with submucosal infiltration but no vascular or lymphatic invasion (Fig 4-5). Resection margins were clear. At six months, EGDS and 68Ga-PET showed no evidence of recurrence or residual disease. This case underlines how, even in Type 3 NETs larger than 20 mm, the pedunculated morphology can allow for complete and safe endoscopic resection, similarly to what is observed in the management of colonic polyps. Further studies are needed to better define the role of morphology in therapeutic strategies for gastric NETs. This is the only reported case of a pedunculated Type 3 NET of this size successfully treated endoscopically.
References
Figure 1. Upper gastrointestinal endoscopy revealed a 20 mm pedunculated polyp in the gastric body, corresponding to a Paris 0-Ip lesion. The surface appeared smooth, with signs of erosion and ulceration.
Figure 2. Linked Color Imaging (LCI) enhanced the vascular and mucosal pattern, showing a well-circumscribed lesion with preserved pit pattern, suggestive of a subepithelial neoplasm suitable for endoscopic resection.
Figure 3. Endoscopic view of the resection using a hot snare technique and prophylactic endoloop placement at the stalk base. Complete resection was achieved without complications.
Figure 4. Hematoxylin and eosin staining, 10x. The tumor arises from histologically normal oxyntic mucosa, without adjacent endocrine hyperplasia, consistent with a sporadic Type 3 gastric neuroendocrine tumor.
Figure 5. Immunohistochemistry panel of the resected specimen. The tumor shows diffuse positivity for Chromogranin A, Synaptophysin, and Somatostatin Receptor 2 (SSTR2). The Ki67 (MIB-1) proliferation index was 8%, consistent with a Grade 2 NET. No lymphovascular invasion was identified, and resection margins were clear.