Epstein-Barr Virus-Associated Early Gastric Carcinoma with Lymphoid Stroma Mimicking a Submucosal Tumor: A Typical Case Diagnosed by Endoscopic Resection and Treated by Local Resection with Sentinel Node Navigation

Gastric cancer with lymphoid stroma (GCLS) accounts for 1%-7% of gastric cancers; ~80% are Epstein-Barr virus (EBV)-positive. The rate of lymph node metastasis is relatively low, even when an early GCLS has invaded the submucosa. We report an early GCLS with massive submucosal invasion mimicking a submucosal tumor (SMT), diagnosed by endoscopic submucosal resection (ESD) and treated with local resection and sentinel node navigation surgery (SNNS). The patient was a 40-year-old Japanese man. A protruding lesion on the greater curvature of the middle part of his stomach was detected by X-ray, and an endoscopic examination revealed a 2.5-cm protruding tumor covered with a normal mucosa and small ulcers at the apex. ESD was performed for a diagnosis. The pathological diagnosis was lymphoepithelioma-like gastric cancer (GCLS), pT1b(SM2), Ly0, V0, pHM1, pVM1. EBV infection in the cancer cells was confirmed pathologically by EBV-encoded RNA. The local resection was performed using SNNS. The patient has had no recurrence or post-gastrectomy syndrome 4 years postsurgery. EBV-associated early GCLS resembling an SMT is relatively rare, and clinicians need to be aware of this disease. Local resection using SNNS may be a surgical option for GCLS cases with a low rate of lymphatic metastasis.