Applicability of endoscopic submucosal dissection for undifferentiated early gastric cancer: Mixed histology of poorly differentiated adenocarcinoma and signet ring cell carcinoma is a worse predictive factor of nodal metastasis

Mixed type tumors should not be considered for endoscopic resection. ESD might be applicable for mucosal tumors with poorly differentiated adenocarcinoma <2 cm and signet ring cell carcinoma <1 cm without lymphovascular invasion.