Incidence and Characteristics of Endoscopic Gastric Polyps in Patients with Autoimmune Atrophic Gastritis: A Multicentric Retrospective Study

Aims Gastric polyps arise from the unusual growth of cells in the gastric mucosa. In autoimmune atrophic gastritis (AAG), the gastric mucosa undergoes morphological and functional alterations, as the disease targets parietal cells, leading to a reduction of stomach acid production (hypo-achlorhydria) and to an increase in gastrin (G) levels (hypergastrinemia). These changes, along with the ongoing inflammation, constitute proliferative stimuli on the gastric mucosa. The aims of this study is to investigate the incidence and the characteristics of gastric polyps in patients with overt AAG managed at six tertiary referral centers in Italy.

Methods This was a multicentric retrospective study on patients who were diagnosed with AAG from January 2000 to June 2023. We collected demographic information, clinical history, biochemical profile, serological data, and results from endoscopic examinations. Moreover, we recorded the histopathological characteristics of any gastric polyps found at endoscopy.

Results The study included 375 patients with AAG [282 female (73.4%), median age 66 years (IQR 54-73)]. They were followed up for a median of 4 (IQR 2-7) years during which they underwent a median number of two upper gastrointestinal endoscopies. The median plasma G levels observed were 646 (IQR 316-1150 pg/ml). 189 (50.4%) patients had at least one incidental polyp. Among these, 152 (80.4%) patients exhibited 204 non-endocrine lesions: 148 (72.5%) were inflammatory polyps, 27 (13.2%) adenomatous polyps, 18 (8.8%) fundic gland polyps, 10 (4.9%) adenocarcinomas, and one MALT lymphoma. Additionally, among the overall population with polyps, 77 patients (40.7%) had gastric neuroendocrine tumors (gNETs), with 40 patients (21.2%) presenting both gNETs and non-endocrine polyps. The median diameter of the detected polyp was 4 (IQR 2-8) mm. Patients with detected polyps tended to be older than those without (median ages 62 vs. 54.5 years, p=0.0006). Moreover, levels of plasma G and chromogranin A (CgA) were significantly higher in patients with polyps than in those without (median gastrin 813 pg/ml vs. 582 pg/ml, p=0.010; CgA 198.0 ng/ml vs. 129 ng/ml, p=0.001). No differences in terms of OLGA and OLGIM stages or H. pylori status were observed between patients with and without polyps.

Conclusions This retrospective study, conducted across multiple centers, draws attention to the notable occurrence of endoscopic lesions, presenting as polyps, in individuals with AAG. Our data indicate that these lesions encompass both gNETs and various non-endocrine lesions, including inflammatory, adenomatous, and fundic gland polyps. A small proportion of patients also developed gastric adenocarcinoma. These results emphasize the importance of proactive endoscopic monitoring and comprehensive histopathological evaluation in patients with AAG, to effectively identify and manage these different gastric lesions.

Conflicts of interest

Authors do not have any conflict of interest to disclose.

Publication History

Article published online:
15 April 2024