A case of cytomegalovirus colitis following immunosuppressive treatment for pyoderma gangrenosum

We report a case of pyoderma gangrenosum (PG) complicated by cytomegalovirus (CMV)-induced colitis. A 79-year-old woman with PG was treated with corticosteroid and cyclosporin. She had blood in her stool and advancing anemia during the treatment. A colonoscopic biopsy specimen from the colon revealed typical CMV-infected cells with CMV inclusions confirmed by immunohistochemistry. Furthermore, there were many CMV-antigen-positive leukocytes, suggesting an active CMV infection, which is serious in compromised hosts. Although ulcerative colitis and Crohn's disease are well known as complications of PG, CMV enterocolitis should be considered in the differential diagnosis of enterocolitis in immunocompromised patients.