Gastric Schwannoma: A Rare Cause of a Gastric Submucosal Mass

Abstract

Purpose: To demonstrate a rare cause of a gastrointestinal submucosal mass that can be difficult to diagnose endosonographically. Case Presentation: A healthy, 23 year-old female was referred for dyspepsia. An upper endoscopy demonstrated an incidental 1.5-cm submucosal mass in the gastric antrum. Manipulation with biopsy forceps suggested a firm mass. Endoscopic ultrasound was demonstrated an ovoid, well-circumscribed hypoechoic heterogeneous mass measuring 1.32 x 1.09 cm arising from the muscularis propria layer of the gastric wall. Transgastric fine needle aspiration was performed with a 22 gauge needle. The cytology obtained showed limited spindle cells and was non-diagnostic. Despite non-diagnostic cytology, the endosonographic findings were concerning for a gastric gastrointestinal stromal tumor. The patient was referred to general surgery and after discussion of management options, the patient elected to undergo laparoscopic partial gastrectomy. The gross specimen demonstrated a yellow-brown nodule measuring 1.5cm. Pathology confirmed the mass was consistent with a gastric schwannoma with strongly positive for s100, while negative for CD34, CD117, desmin, pan-cytokeratin, and smooth muscle actin. The patient had an uneventful surgical recovery. Conclusion: Gastric schwannomas are a rare benign tumor of the gastrointestinal tract. The endosonographic features mimic the appearance of gastrointestinal stromal tumors. The hypocellularity of the fine needle aspirate further complicates identification of this tumor prior to surgical resection.Figure: Firm antral submucosal mass.Figure: FNA of submucosal lesion.