[Immunodeficiency and immunocompromised patients. Opportunistic infection of the lungs].

The number of patients suffering from innate, acquired or iatrogenic immunodeficiency is constantly rising. Thus the number of clinically relevant infections caused by rare or unusual pathogens is also increasing. Histopathological investigations allow the identification of difficult to culture infectious agents as well as the differentiation of tissue invasive infections from superficial colonization. In this review morphological reaction patterns and their differential diagnoses of the most common bacterial, viral and mycotic infections in the lungs of immunocompromised patients are discussed.