What happened, in summary

A 73-year-old man had undergone periodic upper endoscopy since 1999. Review of those examinations later showed a small submucosal-looking gastric protrusion beginning around 2000 and gradually enlarging over many years. By 2017, the lesion measured about 25 mm and had developed a slit-like opening with mucus drainage.

Biopsy raised suspicion for gastric adenocarcinoma of fundic gland type, a rare tumor arising from cells that resemble the stomach’s fundic glands. Imaging showed no metastasis, and endoscopic ultrasound suggested that the lesion remained within the inner wall layers. Endoscopic submucosal dissection was therefore performed to remove the tumor and establish the diagnosis.

Pathology confirmed fundic gland-type gastric adenocarcinoma measuring 17 by 14 mm. The tumor involved the mucosal layer and did not show stromal invasion, lymphatic invasion or vascular invasion. However, neoplastic glands were present at the vertical resection margin.

Because of the positive margin, additional resection was discussed. He decided against further surgery and continued surveillance instead. At 3 months after the endoscopic resection, no local recurrence had been observed.