Hyperplastic polyps arising in autoimmune metaplastic atrophic gastritis patients: is this a distinct clinicopathological entity?

Objectives: Gastric hyperplastic polyp (GHP) commonly arises in the abnormal surrounding mucosa, including autoimmune metaplastic atrophic gastritis (AMAG). We aimed to compare clinicopathological features in patients with GHPs associated with AMAG with those in patients with GHPs associated with non-AMAG. Patients and methods: A total of 1170 patients with GHP(s) were enrolled, and their clinical and pathological data were analyzed, retrospectively. Results: The GHP patients were divided into 181 A-GHP (type A GHP, AMAG-associated GHP) participants, 312 B-GHP (type B GHP, Helicobacter pylori infection-associated GHP) participants, and 677 other GHP participants (non-A-GHP and non-B-GHP) based on pathological status of the surrounding non-polypoid mucosa. The A-GHP patients were older and predominantly female (p < .05). Gastroscopically, A-GHPs showed less distal and more multiple-region distribution in the stomach (p < .001). In addition, the A-GHPs were observed to be usually numerous (55.8%), larger (mean maximum diameter 12.3 mm), and more pedunculated or sub-pedunculated (45.3%) (p < .001). Histopathologically, the intestinal metaplasia, intraepithelial neoplasia, and carcinomatous transformation within GHPs were present in 24.3%, 9.9%, and 2.8% of AMAG patients, respectively, which were significantly higher than those in the B-GHPs and other GHPs (p < .05). However, the differences of intraepithelial neoplasia and adenocarcinoma in surrounding non-polypoid mucosa did not reach statistical significance (p > .05). Conclusions: The GHP(s) arising in AMAG patients is a distinct subgroup of GHP(s) and was an important precancerous lesion. The biopsy from surrounding non-polypoid mucosa was essential to evaluate the underlying etiology of the GHPs, and endoscopists should pay attention to these.