Gastric Schwannoma Mimicking a Gastrointestinal Stromal Tumor: A Case Report

Gastric schwannomas are rare benign peripheral nerve sheath tumors of the gastrointestinal tract and may closely mimic gastrointestinal stromal tumors (GIST) clinically, endoscopically, and radiologically. We present a 67-year-old man who was evaluated for microcytic anemia and found to have a large submucosal gastric mass initially suspected to be a GIST. Contrast-enhanced computed tomography demonstrated a 53 × 46 × 71 mm mural lesion extending into both the gastric lumen and the extragastric space. Laparoscopic wedge resection was performed. Histopathological and immunohistochemical examination established the diagnosis of gastric schwannoma, with tumor cells showing positivity for S100 and SOX10 and negativity for CD117, DOG1, and CD34.This case highlights the diagnostic difficulty in distinguishing gastric schwannoma from GIST preoperatively. Gastric schwannoma should therefore be considered in the differential diagnosis of gastric submucosal masses with imaging and endoscopic features suggestive of GIST. Histopathological examination combined with immunohistochemical evaluation plays a central role in establishing the definitive diagnosis.