What is the most likely diagnosis?

Answer: The endoscopic biopsy specimen obtained from the subepithelial tumor-like lesion revealed adenocarcinoma, pathologically identical to that of primary pancreatic cancer (Fig. 4). Therefore, needle tract seeding of pancreatic cancer into the stomach was diagnosed.

EUS-FNA is a useful and relatively safe diagnostic modality for pancreatic cancer; the adverse event rates are very low (<1% in large centers) and the risks of tumor seeding are lower compared to transcutaneous methods [1]. However, as the number of EUS-FNA increases, the possibility of needle tract seeding occurring after EUS-FNA should always be minded [2]. Especially, in cases when surgical resection does not include the needle tract, such as cancers in the body or tail of the pancreas, EUS-FNA should be cautiously considered and the number of needle passes should be minimized. Close periodical examinations including gastroscopy should be scheduled for patients who undergo EUS-FNA without needle tract resection [3]. In summary, even though needle tract seeding is a rare adverse event of EUS-FNA in pancreatic cancer, it can occur, especially when the cancer is located in the body or tail of the pancreas.