Liver Metastasis of Early Gastric Cancer with Mixed Histology after Endoscopic Submucosal Dissection

The Japanese Classification of Gastric Carcinoma histologically classifies endoscopically resected gastric cancer into differentiated and undifferentiated types according to the presence or absence of tubular structures on histology. The former includes papillary adenocarcinoma and tubular types, and the latter includes poorly differentiated adenocarcinoma, signet ring cell carcinoma and mucinous adenocarcinoma. However, gastric cancer sometimes contains a mixture of differentiated and undifferentiated components, and the clinical outcomes of the histological mixture are unknown, especially following endoscopic resection of early gastric cancer (EGC). This case was within the guideline indications for endoscopic submucosal resection (ESD), although it contained a partly signet ring cell carcinoma component; it recurred after 19 months with multiple lymph node and liver metastases. This case shows that additional surgical resection after ESD should be performed for patients with any mixed signet ring cell component, even in mild or moderately differentiated EGC.