Pyloric, pseudopyloric, and spasmolytic polypeptide-expressing metaplasias in autoimmune gastritis: a case series of 22 Japanese patients

Yasuhiro Wada,Akiko Yoshida,Ryoji Kushima,Kazuo Yamamoto,Kazunari Murakami,Hiroshi Hasegawa,Ken-Ichi Mukaisho,Takahisa Nakayama,Shizuki Takemura,Naoko Mori,Shigemi Nakajima,Shinji Umano,Hiroyuki Sugihara

doi:10.1007/s00428-021-03033-5

Abstract

There are two types of pyloric gland-like metaplasia in the corpus of stomach: pyloric and pseudopyloric metaplasias. They show the same morphology as the original pyloric glands in H&E staining. Pseudopyloric metaplasia is positive for pepsinogen (PG) I immunohistochemically, whereas pyloric metaplasia is negative. Recently, spasmolytic polypeptide-expressing metaplasia (SPEM) is proposed for pyloric gland-like metaplasia mainly in animal experiments. SPEM expresses trefoil factor family 2 (TFF2) and is often considered synonymous with pseudopyloric metaplasia. We reviewed consecutive 22 Japanese patients with autoimmune gastritis (AIG) to investigate TFF2 expression in pyloric and pseudopyloric metaplasias by counting all pyloric gland-like glands in biopsy specimens taken from greater curvature of the middle corpus according to the Updated Sydney System. Pyloric metaplasia was seen in all the 22 cases, and pseudopyloric metaplasia was found in 15 cases. Of 1567 pyloric gland-like glands in all the cases, 1381 (88.1%) glands were pyloric metaplasia glands, and the remaining 186 (11.9%) glands were pseudopyloric metaplasia glands. TFF2 expression was observed in pyloric or pseudopyloric metaplasia glands in 20 cases. TFF2 expression was recognized in 409 of 1381 (26.9%) pyloric metaplasia glands and 27 of 186 (14.5%) pseudopyloric metaplasia glands (P<0.01, chi-square test). In conclusion, SPEM was not always the same as pseudopyloric metaplasia in human AIG, and the majority of metaplasia in AIG was not pseudopyloric but pyloric metaplasia.

Highlights

Metaplasia is a phenomenon in which one adult cell type is replaced by another adult cell type [1]
We examined the numbers of trefoil factor family 2 (TFF2) expressing glands in pyloric/pseudopyloric metaplasia glands and confirmed whether spasmolytic polypeptide-expressing metaplasia (SPEM) can be used for pseudopyloric metaplasia in human materials
The size of each section was measured and the cell density was calculated per each section AIG autoimmune gastritis, H+ /K+ -ATPase hydrogen potassium ATPase, ECL cells enterochromaffin cell-like cells

Summary

Introduction

Metaplasia is a phenomenon in which one adult cell type is replaced by another adult cell type [1]. Various types of metaplasias have been described. Intestinal metaplasia is one of the representative metaplasias in the stomach which consists of large or small intestinal mucosa located in the places where gastric mucosa should have existed [1]. Pyloric/pseudopyloric metaplasia is another representative metaplasia which consists of pyloric gland mucosa located in the places where fundic gland mucosa should have existed [2,3,4]. Pancreatic acinar cell metaplasia is a cluster composed of pancreatic acinar cells in stomach [5,6,7]. Pyloric metaplasia is stained same as original pyloric gland mucosa with hematoxylin and eosin (H&E) and with immunohistochemical staining for MUC6.

Methods

Results

Conclusion