Cytomegalovirus superinfection is associated with a poor prognosis in non-HIV Pneumocystis pneumonia (PCP) and can cause deterioration of PCP not only simultaneously but also after initiating PCP treatment. Cytomegalovirus pneumonia should be considered in cases with deterioration after initiating PCP treatment; multiple nodular lesions are useful findings for the diagnosis.
Keywords: Cytomegalovirus pneumonia; Pneumocystis pneumonia; immunocompromised host.