BackgroundCytomegalovirus (CMV) infection, often subclinical in childhood, is reactivated during a state of cell-mediated immunodeficiency. In cases of organ damage, patients can require medical treatment for an infectious disease, generally through the use of antiviral drugs. There are no reports of surgical treatment in cases, where infection was found, and medical treatment was difficult. We encountered a case of CMV enteritis that was difficult to treat because of resistance to antivirals but improved after total colectomy.Case presentationA previously healthy, 74-year-old woman visited a doctor with a chief complaint of watery diarrhea persisting for 2 weeks; she was transferred to our hospital because of hypoxemia and hypovolemic shock. Computed tomography scan indicated wall thickening over the entire colon and the patient was diagnosed with infectious colitis. Conservative and antibacterial therapies were started with fasting fluid replacement. Subsequently, bloody stools were observed 11 days after admission. Colonoscopy was then performed, which showed mucosal edema and longitudinal ulcer, while a histopathological examination of the colon mucosa revealed C7HRP positive on 22 days after admission. CMV enteritis was diagnosed, and the antiviral medication, ganciclovir, was started. Diseases causing immunosuppression and other possible causes of enteritis were also closely examined; however, all were negative. Furthermore, the patient’s symptoms and her endoscopic findings did not improve with ganciclovir administration; therefore, the antiviral drug was changed to foscarnet. Unfortunately, the patient did not improve despite the additional administration of gamma globulin and methylprednisolone, and she was determined to have enteritis resistant to medical therapy. A total colon resection was performed 88 days after the admission. Her condition gradually stabilized postoperatively, and oral intake was initiated and tolerated. The patient was transferred to another hospital for rehabilitation for home discharge. She is now at home and has had no recurrences.ConclusionsIn previous reports of surgical treatment for CMV enteritis, many cases were initially undiagnosed, emergency surgery was performed after perforation or stenosis was recognized, and then CMV was diagnosed and treated. In CMV enteritis without immunodeficiency, surgical treatment may be an option if medical treatment is ineffective.