Atypical Cytomegalovirus-Associated Oral Ulcerations Mimicking Aphthous Lesions in a Child Receiving Blinatumomab: A Case Report.

Cytomegalovirus (CMV) is an opportunistic pathogen that can rarely cause ulcerative lesions of the oral mucosa in immunocompromised patients, although such manifestations often mimic other infectious, inflammatory, or traumatic etiologies. We report the case of a two-year-eight-month-old child with B-cell acute lymphoblastic leukemia undergoing blinatumomab therapy as a bridge to hematopoietic stem cell transplantation, who developed atypical, painless erosive glossitis. Clinical examination revealed polycyclic aphthoid lesions on the dorsum of the tongue in an afebrile, immunosuppressed patient. Virological polymerase chain reaction performed on lesion swabs and plasma detected CMV DNA, whereas tests for herpes simplex virus, varicella-zoster virus, Epstein-Barr virus, and enterovirus, as well as mycological microscopic examination, were negative. These findings supported the diagnosis of CMV-associated ulcerative glossitis. The lesions resolved following discontinuation of blinatumomab and initiation of empirical antiviral and antifungal therapy. This case highlights the diagnostic challenges of CMV mucosal involvement in immunocompromised hosts, particularly in the absence of classic ulcerative features or confirmatory tissue biopsy. Detection of CMV in mucosal swabs requires careful interpretation, as asymptomatic shedding is common. Recognizing such atypical presentations is essential to guide appropriate diagnostic workup and therapeutic decision-making in high-risk pediatric oncology patients.