Fig. 2. Sigmoidoscopy performed on day 40 revealed active bleeding with multiple hemorrhagic ulcers throughout the colon (A). Endoscopic biopsy revealed a chronic inflammatory ulcer (B). Histopathologic staining did not show any inclusion-bearing cells typical of CMV infection (owl's eye inclusions); however, immunohistochemical staining identified immunoreactivity for CMV antigen (C).