Xanthogranulomatous inflammatory reaction associated with endoscopic mucosal resections of gastric and colonic cancer

Background and aim: Xanthogranulomatous inflammatory reaction (XGI) is a rare diagnosis in the gastrointestinal tract. It could be misinterpreted as an invasive cancerous lesion. The pathogenesis of XGI in the gastrointestinal tract (GIXGI) is not well understood. We clinicopathologically studied six cases of GIXGI associated with endoscopic biopsy, mucosal resection, and submucosal dissection of gastric and colonic adenocarcinoma. Methods: Immunohistochemical, special histochemical stains, and tuberculosis-polymerase chain reaction (PCR) were performed. All radiological images and medical records of the patients were reviewed. Results: All cases showed XGI with foamy histiocytes, lymphocytes, and foreign body-type giant cells, which were positive for CD68 and negative for CD117, S-100, and cytokeratin. Acid-fast, Gomori's methenamine silver, periodic acid Schiff stains, and nontuberculous Mycobacterium and Mycobacterium tuberculosis-PCR were also negative. Two of four gastric adenocarcinomas were suspected to be advanced gastric cancer by computed tomography staging. However, the microscopic examination revealed only XGI with a mucosal carcinoma or without any residual tumor cells in the gastric wall. Conclusions: GIXGI may simulate advanced carcinoma clinicoradiologically. GIXGI should be included in the differential diagnosis in the case suggestive of a rapid transition to advanced gastrointestinal carcinoma within 12 weeks from the preoperative endoscopic procedure.