Gastric malignant schwannoma presenting with upper gastrointestinal bleeding: a case report

INTRODUCTION: We report a case of gastric malignant schwannoma presenting with gastrointestinal bleeding. CASE PRESENTATION: A 70-year-old Japanese man presented with gastrointestinal bleeding to our hospital. Gastrointestinal endoscopy revealed a protruding lesion in the gastric body. Hematoxylin and eosin staining of biopsy specimens from this lesion revealed sheets of spindle cells. Immunohistochemistry revealed that these cells were positive for S-100 protein and negative for c-Kit and smooth muscle actin. Because mitosis was diffusely visible, this tumor was diagnosed as a gastric malignant schwannoma. Distal gastrectomy with lymph node dissection was performed and the patient's postoperative course was uneventful. However, five months after the surgery, he died from multiple liver metastases. CONCLUSION: Cases of gastric malignant schwannoma have rarely been reported. The efficacy of surgical resection and postoperative prognosis continues to remain unclear and should be investigated further.