Isolated gastric malakoplakia: a case report and review of the literature.

A 62-year-old African American woman presented with weight loss and dyspepsia. She did not have any clinical evidence of immunodeficiency. Upper gastrointestinal endoscopy revealed multiple small polypoid lesions in the gastric body and fundus that appeared larger and more erythematous than usual fundic gland polyps. Examination of biopsy specimens revealed an infiltrate of large histiocytes with eosinophilic granular cytoplasm located in the lamina propria and containing Michaelis-Gutmann bodies. These histologic findings were diagnostic of gastric malakoplakia. Gastrointestinal malakoplakia is uncommon, and exclusive gastric involvement is extremely rare. Because occult bacterial infection has been postulated as the underlying cause of malakoplakia, the presence of Helicobacter pylori infection was investigated using immunohistochemical and serologic techniques, and the presence of Yersinia enterocolitica or Yersinia pseudotuberculosis infection was investigated by polymerase chain reaction assay. There was no evidence of H pylori, Y enterocolitica, or Y pseudotuberculosis in these biopsy specimens, and there was no evidence of malakoplakia or concurrent malignancy at any other site. Follow-up examination 12 months later revealed no endoscopic or histologic improvement.