Endoscopic findings. (A) Initial examination shows 15-mm sized mucosal depression containing shallow ulcer with irregular border on gastric angle. Biopsy was performed on the ulcer margin at a local clinic. (B) Follow-up examination after one week demonstrates enlargement of ulcer crater, the surface of which is covered with whitish exudates. (C) Follow-up examination performed three weeks later reveals that previously noted ulcer has healed and the surrounding mucosal depression has become nodular and hyperemic. (D, E) On follow-up examination carried out six weeks later, reddish ulcer scar with nodular lesion is seen. When this lesion is stained with indigocarmine, it looks flat or slightly elevated compared to mucosal depression seen on initial examination.

Microscopic findings of gastric biopsy specimen. (A) Features of signet ring cell adenocarcinoma is seen (arrows) (H&E, ×200). (B) Pan-cytokeratin (CK) immunohistochemical stain reveals positive atypical cells which are brownish colored cells (CK stain, ×400).