Systemic cytomegalovirus masquerading as a colorectal mass in a patient with undiagnosed HIV/AIDS.

Introduction: Cytomegalovirus (CMV) infection is common among patients with human immunodeficiency virus (HIV) infection. Gastrointestinal (GI) involvement with tumor like lesion is a rare presentation. Our patient presented with rectal pain and findings concerning for malignancy. Subsequently our patient was diagnosed with acquired immunodeficiency syndrome (AIDS), CMV viremia and CMV proctitis. Case: A 37-year-old man who reported having sex with men presented with severe proctalgia and hematochezia. Imaging showed irregular rectal wall thickening concerning for malignancy. Sigmoidoscopy revealed a circumferential necrotic lesion suspicious for malignancy. Surprisingly, biopsy showed a cytopathic effect compatible with CMV infection. In addition to testing positive for CMV, patient was newly diagnosed with HIV/AIDS, hepatitis C, syphilis, and gonorrhea. CMV infection was treated with ganciclovir, which resulted in a significant response. Ganciclovir was later replaced with valganciclovir. Valganciclovir was continued and antiretroviral therapy (ART) was started as an outpatient and with resolution of symptoms. Discussion: CMV infection is one of the most common opportunistic infections among patients with HIV infection. Several cases of CMV colitis were reported among immunocompromised patients. Our patient's presenting symptoms and direct visualization of rectal lesion were not only deceptive but also unique. As what looked like a rectal malignancy was later diagnosed as tissue invasive CMV by biopsy. Invasive CMV infection should be managed with ganciclovir. Conclusion: GI CMV as the initial presentation of HIV is rare. Moreover, CMV proctitis can masquerade as a rectal cancer and clinicians should be aware of this rare presentation of CMV.