Gastric Schwannoma Masquerading as a Gastrointestinal Stromal Tumor: A Case Report and Diagnostic Challenges

Abstract

Gastric schwannomas (GSs) are rare, benign mesenchymal tumors originating from Schwann cells of the nerve sheath, accounting for approximately 0.2% of all gastric tumors. These tumors pose diagnostic challenges due to their resemblance to gastrointestinal stromal tumors (GISTs) and other submucosal neoplasms. We present the case of a 47-year-old male with a history of GI bleeding who was initially diagnosed with suspected GIST based on an enhanced abdominal computed tomography scan. The scan revealed a 7.4 × 5.6-cm exophytic mass with homogeneous enhancement in the gastric antrum. Laparoscopic distal gastrectomy with Roux-en-Y gastrojejunostomy was performed, revealing a tumor with purple-red discoloration, serosal invasion, omental involvement, and suspected metastatic infra-pyloric nodules. Histopathological examination confirmed a GS, characterized by spindle-shaped cells with Antoni A and B patterns, Verocay bodies, and strong S-100 protein immunoreactivity, while negative for CD117, DOG-1, CD34, SMA, and desmin. The patient recovered uneventfully and was discharged on postoperative day 6. This case underscores the diagnostic complexity of GSs, emphasizing the critical role of histopathological and immunohistochemical analysis in distinguishing them from other mesenchymal tumors. Minimally invasive surgical resection offers both diagnostic confirmation and effective treatment, with favorable oncologic and functional outcomes.