Answer: Fundic gland polyp

Histology: This biopsy taken from the body of the stomach shows cystically dilated, tortuous and budding fundic glands lined by parietal cells, chief cells and mucous neck cells. There is focal apical “snouting” of the parietal cells suggestive of proton pump inhibitor therapy. The overlying epithelium is normal in appearance. No dysplasia is present.

Discussion: Fundic gland polyps (FGP), also known as Elster’s polyps, occur in the oxyntic mucosa both in the setting of familial adenomatous polyposis (FAP) syndrome as well as outside of it, but more commonly in the former setting. Spontaneous regression occurs. In the syndromatic setting, the patients are younger and most of them female. Variously regarded as hyperplastic, neoplastic and hamartomatous, these have no clinically significant malignant potential. There is some evidence to support a possible causal relationship between the use of Omeprazole, a proton pump inhibitor and development of FGP.

FGP are usually small, less than 0.5 cm in size, sessile & smooth surfaced. They may be numerous and may carpet the mucosa. Hyperplastic expansions of the deep epithelial compartment of oxyntic mucosa with budding are represented in collections of assorted, distorted, cystically dilated oxyntic glands with overlying short pits. The cysts are of various shapes and sizes and are lined by oxyntic, chief and mucus neck cells. The overlying surface and foveloar epithelium may be atrophic, normal or dysplastic. When dysplasia occurs, it is usually low grade, rarely high grade and may be seen in both the syndromatic and non-syndromatic settings. Dysplasia is more common in the FAP associated FGP. FAP associated FGP have APC mutations where as sporadic FGP have beta catenin mutation. These observations suggest that these are indeed probable neoplasms, however, progression to carcinoma is vanishingly rare.

FGP are not regarded as premalignant lesions of clinical significance.