A 50-year-old woman was found to have a tumor shadow on the posterior wall of the gastric cardia on X-ray examination. Gastroendoscopy revealed a submucosal tumor-like, elevated lesion with a depression. Magnifying endoscopy showed an abnormal microvascular pattern in the depression. Biopsy examination of the lesion revealed signet ring cell carcinoma. Endoscopic ultrasonography revealed a low-echogenic, solid mass mainly in the third layer. Interpretation of images of the 4th layer and deeper tissues was difficult due to the location. Its invasion depth was diagnosed as T2. Proximal gastrectomy was performed. Pathological examination revealed infiltration of signet ring cell carcinoma in the mucosal layer, and poorly differentiated solid adenocarcinoma with lymphoid stroma in the submucosal layer. The final diagnosis was T3 cancer, 23×20 mm in size, without lymph node metastasis. The lesion was positive for Helicobacter pylori but negative for Epstein-Barr virus.
