Thursday 10 November 2005
Although many common enteroviruses are believed to infect the gastric mucosa, so few patients with acute gastroenteritis undergo gastric biopsy that no information is available on the morphologic features of these infections.
The only viral infections of the stomach with a distinct pathologic appearance are those caused by cytomegalovirus (CMV); CMV-associated gastritis is seen almost exclusively in children and immunocompromised patients.
Usually it is associated with concurrent CMV infection of other sites of the digestive tract. Endoscopically, the gastric mucosa may appear completely normal or show erosions or shallow ulcers.
Rarely, it may present as a grossly nodular mucosa that has been referred to as a pseudotumor.
In children, a hypertrophic gastritis similar to Menetrier’s disease may develop.
The histopathologic appearance varies depending on the patient’s ability to mount an immune response.
In some patients, particularly those with very low CD4 counts, numerous CMV inclusions may be seen in epithelial and endothelial cells as well as in macrophages, with little or no inflammatory response in the adjacent tissues.
In other patients, one may see a florid mixed inflammatory reaction with abundant granulation tissue, and typical CMV inclusions may be difficult to detect without using immunohistochemistry or in situ hybridization techniques.
Intense eosinophil infiltration in the lamina propria accompanied by peripheral eosinophilia has been noted, suggesting an allergic component to the gastritis in some patients.
- infectious gastritis