Campylobacter concisus gastritis masquerading as Helicobacter pylori on gastric biopsy.

Abstract

Campylobacter concisus is a Gram-negative rod closely related to Helicobacter pylori. We sought to identify gastric biopsies positive for C. concisus that had been misdiagnosed as H. pylori gastritis in our routine surgical pathology practice. We performed a retrospective review of gastric biopsies in our regional microbiology and pathology electronic records to identify cases that were submitted for H. pylori testing in which C. consicus was identified on culture and how many had concurrent biopsies sent to pathology for histologic assessment over a two-year period (2017-2018). Pathologic findings in the gastric biopsies were reviewed and immunohistochemical staining for H. pylori was performed. 50 of 2191gastric biopsy specimens submitted to microbiology in 2017-18grew C. concisus (2.3%), compared to 168 in which H. pylori was identified (7.7%). Twenty-eight cases had concurrent histology. A total of four cases (three from 2017 and one from 2018) demonstrated organisms morphologically identical to H. pylori in the H&E sections, of which all were H. pylori immunoreactive. Our case series is the first to demonstrate that C. concisus can mimic H. pylori gastritis in routine biopsy pathology.