Bacteria

Morphology

Cytology: 
Large, tightly coiled, spiral-shaped bacteria, often with pronounced corkscrew morphology. Usually sparse, located along the mucus layer and surface epithelium. Background inflammation variable, often mild.

Histology:
Organisms located within the surface mucus layer and gastric pits, usually focal and patchy. The associated chronic gastritis is typically mild to moderate and often lacks significant activity. Neutrophils are usually sparse or absent. Lymphoid aggregates may be present, with possible association with MALT-type lesions. The bacterial density is generally lower than in Helicobacter pylori infection. Often underdiagnosed due to low organism density and patchy distribution.

Special stains (Giemsa, Warthin-Starry, Steiner) may increase detection rate, but sensitivity is limited due to low bacterial density. Immunohistochemistry for Helicobacter pylori often negative or only weakly reactive.

Differential Diagnosis:

• Helicobacter pylori - shorter, slightly coiled, S-shaped organisms, usually higher density.
• Other spiral or Campylobacter-like organisms in contaminated samples.

Clinical notes

Chronic gastritis, peptic ulcer disease. Reported association with gastric MALT lymphoma. Zoonotic origin suspected, commonly linked to contact with dogs, cats, or pigs. (1)

Ancillary Testing

Additional Information

It is now recognized that H. heilmannii s.l. does not represent a single species, but rather a group of distinct gastric non-H. pylori Helicobacter species.