Abstract
Cytomegalovirus (CMV) reactivation is well known in post-transplant immunocompromised children. However, the incidence in non-transplant patients is significantly less, and only scarce case reports are available in the literature regarding CMV disease in children with solid tumors. We present a 3-year-old male child with multisystem refractory Langerhans cell histiocytosis, who had very high CMV viremia and disseminated CMV infection with secondary hemophagocytic lymphohistiocytosis and was successfully treated without organ damage and sequelae. Although routine screening is not recommended, CMV viremia/disease needs to be considered in non-transplant immunocompromised children with multisystem involvement with unexplained cytopenia.