A Novel Intersection - Cytomegalovirus Gastritis Following Cemiplimab and Talimogene Laherparepvec in a Patient with Advanced Cutaneous Squamous Cell Carcinoma: a Case Report

Abstract

Background Immunotherapy, particularly immune checkpoint inhibitors, has revolutionized cancer treatment. While effective, these therapies sometimes result in immune-related adverse events and have been associated with infectious complications. Case presentation: A 63-year-old South Asian man with a history of cutaneous squamous cell carcinoma, previously treated with cemiplimab and talimogene laherparepvec, was admitted to the hospital with dyspepsia of a six-month duration, anorexia, and a 20 kg weight loss requiring initiation of total parenteral nutrition. Esophagogastroduodenoscopy demonstrated extensive ulceration in the gastric antrum, and biopsy showed cytomegalovirus inclusions with positive immunohistochemistry. Additional immunologic studies failed to identify any underlying immunodeficiency state that might have predisposed the patient to cytomegalovirus infection. After seven weeks of intravenous ganciclovir, the patient reported significant improvement of his symptoms, and his total parenteral nutrition was discontinued. Conclusions This case highlights a rare instance of cytomegalovirus reactivation in a patient without prior immune-related adverse events or immunosuppressive therapy, challenging the current understanding of immune checkpoint inhibitors and their association with infections as well as contributes to the evolving landscape of oncology and infectious diseases in immunocompromised hosts, where the interplay between cancer therapy, immune modulation, and infection risk remains a critical area of study.