Abstract
BACKGROUND: Laterally spreading tumours (LSTs) are superficial neoplasms that usually extend laterally along the intra-luminal wall of the gastrointestinal tract. Recently, the incidence of LSTs in the colorectal mucosa has greatly increased. However, LSTs in the stomach are exceedingly rare and have never been previously reported. CASE PRESENTATION: Here, we report a 69-year-old male with epigastric pain and a gastric LST 6 cm in diameter located in the distal stomach and grossly extended into the duodenal bulb. The stomach lesion was initially diagnosed as high-grade intraepithelial neoplasia, while the duodenal lesion was diagnosed as a tubulovillous adenoma. A therapeutic strategy of endoscopic submucosal dissection and distal gastrectomy was applied. The surgeries and postoperative course were uneventful, and the patient remained asymptomatic 1 year after surgery. CONCLUSIONS: This is a clinically significant case, as it provides detailed information regarding laterally spreading early gastric cancer and emphasizes the diagnostic and therapeutic approaches for early gastric cancerous lesions.