A Rare Duodenal Subepithelial Tumor: Duodenal Schwannoma

Schwannomas are uncommon neoplasms that arise from Schwann cells of the neural sheath. Gastrointestinal schwannomas are rare among mesenchymal tumors of the gastrointestinal tract, and only a few cases have been reported to date. Duodenal schwannomas are usually discovered incidentally and achieving a preoperative diagnosis is difficult. Schwannomas can be distinguished from other subepithelial tumors on endoscopic ultrasonography; however, any typical endosonographic features of duodenal schwannomas have not been reported due to the rarity of these tumors. Immunohistochemistry is essential to distinguish schwannomas from gastrointestinal stromal tumors and leiomyomas. We report a case of duodenal schwannoma found incidentally during a health check-up endoscopy. On endoscopic ultrasonography, this tumor was suspected as a gastrointestinal stromal tumor; therefore, the patient underwent laparoscopic wedge resection of the tumor. Histopathology and immunohistochemistry confirmed that the duodenal lesion was a benign schwannoma.