Gastric schwannoma: a clinicopathologic analysis of four cases with emphasis on diagnostic challenges

Gastric schwannoma (GS) is a rare benign mesenchymal tumor that is frequently mistaken preoperatively for a gastrointestinal stromal tumor (GIST) because both lesions commonly present as hypoechoic subepithelial masses arising from the muscularis propria.This distinction is clinically important because GS does not require the risk stratification or oncologic management applied to GIST.We retrospectively analyzed four surgically resected GS cases, focusing on clinicoradiological findings, histopathology, and immunohistochemistry.In all cases, preoperative imaging led to an initial impression of GIST.One patient showed perigastric lymph node enlargement on computed tomography, raising concerns about possible malignant behavior; however, pathological examination confirmed reactive hyperplasia rather than nodal involvement of the tumor.Histologically, the tumors were composed of bland spindle cells and showed peripheral lymphoid cuffing in all four cases.Immunohistochemically, all patients demonstrated diffuse S-100 positivity and were negative for CD117 (c-kit) and smooth muscle actin.All patients underwent minimally invasive resection and were free of recurrence.Our case series highlights that preoperative imaging alone may be insufficient to distinguish GS from GIST, and that perigastric lymph node enlargement does not necessarily indicate malignancy in GS.Definitive diagnosis relies on histopathological and immunohistochemical evaluations.