Endoscopic Submucosal Dissection of Large Gastric Hyperplastic Polyps: Clinicopathological Study From a Single Center.

Background Gastric hyperplastic polyps (GHPs) represent a subset of gastric polyps that are clinically problematic when large and they can cause persistent, low-grade bleeding or gastric outlet obstruction. Rare malignant transformation has been reported, albeit not in our experience. Methods We retrospectively studied the clinicopathologic characteristics of large GHPs (≥20 mm) excised by endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) between 2013 and 2020 at a single institution. Results Ten patients underwent 37 resections by ESD (n=16), EMR (n=15), and snare resection (SR, n=6). For patients with available follow-up endoscopies, the overall recurrence rate was 9/13 (69.2%) for ESD procedures, 14/14 (100%) for EMR procedures, and 2/2 (100%) for SR procedures, with an average follow-up time of 9.4 months. All cases excised by ESD without recurrence had negative deep and lateral margins. The most common adverse event associated with ESD and EMR is bleeding. Histological examination reveals classic features of gastric hyperplasia, including superficial ulceration, granulation tissue with reactive basal atypia, gastropathy and gastritis-like features. There was one case with intestinal metaplasia, yet none revealed dysplasia or neoplasia and all the studied samples were negative for Helicobacter pylori organisms by immunostaining. Conclusions Large GHPs are clinically challenging and difficult to eradicate with a high rate of recurrence when excised by EMR or SR. ESD appears to be more effective than EMR and SR for complete resection. As the deep margins are almost always negative for ESD specimens, it appears that GHP has a field effect with local recurrence at the lateral margins. Pinning and inking the lateral margins of friable specimens intraoperatively may be helpful for pathologic examination.