Now you see me, now you don't: A vanishing papillomatous CMV pseudotumor in an immunocompetent host.

INTRODUCTION: Cytomegalovirus (CMV) is a viral infection that not uncommonly affects immunosuppressed patients, such as patients with HIV, those on chemotherapy, and transplant recipients. We present an unusual case of CMV manifesting as a pseudotumor in an immunocompetent patient. CASE PRESENTATION: A 73-year-old woman had been trapped for seven days under her belongings after a fall before being found. She was admitted for septic shock secondary to an E. coli UTI, with resultant acute kidney injury secondary to rhabdomyolysis. Her course was complicated by a brisk lower GI bleed. Colonoscopy revealed a friable, malignant-appearing anorectal mass concerning for adenocarcinoma. However, the biopsy showed a squamous papilloma with acute and chronic inflammation and papillary fragments of granulation tissue lined by squamous epithelium. Scattered reactive stromal cells stained positive for CMV on immunohistochemistry. CMV serology was negative for IgM and positive for IgG, indicating past infection and latency. CMV PCR was negative. The patient was treated with IV ganciclovir and later completed PO valganciclovir for three weeks. Her bleeding resolved, and she was scheduled for a repeat colonoscopy to assess for resolution of the pseudotumor. Repeat colonoscopy performed at an outside hospital was normal, with complete resolution of the tumor. CONCLUSION: CMV typically presents as a GI infection in immunosuppressed individuals. Risk factors include advanced age, renal failure, sepsis, malnutrition, and trauma. Malnutrition reduces T-lymphocyte counts, increasing susceptibility to infection. Pathogenesis likely involves viral proliferation in the endothelium, leading to vasculitis, thrombosis, and local ulceration. CMV seropositivity is high in immunocompetent adults. However, active disease results from reactivation after a latent phase. Biopsy is the gold standard for diagnosis and shows "owl's eyes," which are basophilic intranuclear inclusions; serology, cultures, and antigen tests can also be used. Treatment includes antivirals such as ganciclovir, foscarnet, and cidofovir. Previous studies have demonstrated that CMV-induced inflammatory tissue, which appears as tumor-like masses, has completely resolved with antiviral therapy. In our patient, bleeding stopped after initiation of therapy, and her follow-up colonoscopy to evaluate the resolution of her pseudotumor confirmed regression of the tumor.