# Malignant transformation of gastric hyperplastic polyps in an autoimmune gastritis patient—a case report and literature review

## TL;DR

A rare case of cancer developing from a gastric polyp in a patient with autoimmune gastritis is reported, highlighting elevated gastrin as a possible risk factor.

## Contribution

This case report highlights the rare malignant transformation of a gastric hyperplastic polyp in autoimmune gastritis and suggests elevated gastrin as a potential cancer risk factor.

## Key findings

- Endoscopic resection successfully treated early-stage cancer from a gastric hyperplastic polyp.
- Elevated gastrin-17 levels may indicate cancer risk in Helicobacter pylori-negative autoimmune gastritis.
- The patient showed no recurrence after one year of follow-up.

## Abstract

The cancer risk in autoimmune gastritis (AIG) remains controversial. Malignant transformation of gastric hyperplastic polyps (GHPs) in an AIG patient is rare. The esophagogastroduodenoscopy (EGD) of a 75-year-old male patient showed a 0.8 cm GHP. Endoscopic resection was conducted, and the pathological findings showed high-grade dysplasia and intramucosal moderately differentiated adenocarcinoma. Follow-up at 1 year confirmed no sign of recurrence. 18 months post-operatively, another EGD confirmed advanced-stage AIG, evidenced by characteristic endoscopic/histologic findings, positive anti-parietal cell antibody, low pepsinogen I/II ratio, significantly elevated gastrin-17, low vitamin B12, and negative Helicobacter pylori (Hp) serology. Concurrent Hashimoto's thyroiditis and vitiligo were also noted. We here report a rare case of early malignant transformation of a small GHP arising in a context of AIG. Elevated gastrin levels may be a potential risk factor for cancer development in Hp-negative AIG. Endoscopic resection can be considered for early-stage cancerous transformation of GHPs.