Human cytomegalovirus infection of the gastrointestinal tract in apparently immunocompetent patients.

Human cytomegalovirus (HCMV) infection is usually reported in immunocompromised patients. This study reports 11 cases of HCMV infection of the gastrointestinal (GI) tract diagnosed in apparently immunocompetent hosts. The median age of the patients studied was 76 years, and the major presenting symptoms were diarrhea, epigastric pain, and abdominal discomfort. The large intestine was involved in 6 cases, the stomach in 4 cases, and the lower esophagus in 1 case. Endoscopy revealed ulcers or hypertrophic folds in the GI tract and single ulcers or erosions in the colon and rectum. Light microscopy showed chronic inflammatory infiltrate in the lamina propria in all cases. The diagnosis of HCMV infection was based on the histological and immunohistochemical identification of HCMV inclusion bodies in different cell types, including epithelial, endothelial, stromal, and smooth muscle cells. Both "classical" inclusions, characterized by an "owl's eye" appearance, and atypical inclusions were found. For all patients, no apparent causes of immunodeficiency were detected at the time of diagnosis of HCMV infection. At follow-up, however, 4 patients were found to harbor a malignant tumor (ie, pancreas, lung, Vater's papilla, and extrahepatic bile duct) at an interval of 2 to 5 months after the diagnosis of HCMV infection. Especially in elderly patients, HCMV infection of the GI tract might be an early clue to the presence of immunologic defects induced by an underlying neoplasia.