A case of small undifferentiated intramucosal gastric cancer with lymph node metastasis.

Early gastric cancer (EGC) has a favorable prognosis after surgical gastrectomy. For intramucosal EGC with little risk of lymph node metastasis, endoscopic mucosal resection (EMR) is an accepted treatment method. Herein we document a noteworthy case of small undifferentiated gastric cancer with nodal metastasis. A 60-year-old Japanese woman underwent gastrectomy with D2 lymph node dissection for the treatment of EGC in the lower gastric body. Histological examination revealed that signet-ring cell carcinoma was located in approximately one-third of the superficial portion of the mucosal layer, with a tumor size of 13 mm. No lymphatic invasion, venous invasion, or fibrosis was observed in the submucosal layer. This case had nodal metastasis and was finally diagnosed as stage IB (T1N1M0) according to the Japanese Classification of Gastric Carcinoma (JCGC). The patient is alive without recurrence 6 years after treatment.