Signet Ring Cell Carcinoma Mimicking Gastric Gastrointestinal Stromal Tumor: A Case Report

The presentation of submucosal gastric cancer, especially signet ring cell carcinoma, is rare. The submucosal tumor (SMT) is covered with normal mucosa, and confirmation is difficult through endoscopic biopsy; thus, histologic diagnosis is important to determine the appropriate treatment method. Here, we report a case of gastric signet ring cell carcinoma mimicking gastrointestinal stromal tumor (GIST). A 2-cm-sized SMT suspected of being a GIST on preoperative endoscopic ultrasonography and computed tomography was suspected to be cancerous during surgery. The frozen diagnosis of the resected mass (obtained via wedge resection) showed a carcinoma with signet ring feature, and additional frozen diagnosis of one enlarged lymph node revealed metastatic cancer. Therefore, subtotal gastrectomy with lymph node dissection was performed. This case report suggests that preoperative histologic diagnosis of high-risk SMT might be useful, although the tumor had typical features of GIST on preoperative imaging. Overall, if a tumor is suspected of being a gastric carcinoma during surgery and the differential diagnosis between gastric carcinoma and GIST is uncertain, a careful surgical approach should be considered to account for the possibility of adenocarcinoma.