Helicobacter heilmannii gastritis: a case study with review of literature.

H. heilmannii belongs to the Helicobacter family and is found in a small number of gastric biopsies. This bacterium is generally found in primates, cats, pigs, and carnivorous mammals. About 0.5% to 6% of human gastric infections have been attributed to H. heilmannii. The bacterium usually induces mild chronic gastritis but may be associated with peptic ulceration, and rare cases were reported in association with gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. We report a case of H. heilmannii chronic gastritis in a 44-year-old man with a history of chronic heartburn, found to have erythema and granularity in the antrum. Antral biopsy showed mild chronic gastritis with prominent lymphoid aggregates, and rare long, thin, spiral bacilli were present adjacent to the surface epithelium. The long tightly coiled morphology suggestive of H. heilmannii was obvious at 1000 x magnification. The lack of information in the literature regarding cross-reactivity of H. heilmannii to commercially available antibodies used for immunohistochemical detection of H. pylori prompted us to evaluate whether commercially available polyclonal anti-H. pylori antibodies show cross-reactivity between the two organisms. The H. pylori immunostain highlighted H. heilmannii organisms and their characteristic morphology, confirming cross-reactivity with the anti-H. pylori polyclonal antibody. This case illustrates the potential contribution of commercially available polyclonal antibodies against H. pylori to help confirm a diagnosis of H. heilmannii gastritis. The use of immunohistochemical stain to identify H. heilmannii may be useful in cases with a paucity of organisms, with suggestive but not diagnostic forms on routine hematoxylin and eosin stain.