In the late stage after cyclophosphamide treatment no inflammatory response was observed and A. fumigatus rapidly colonised the pulmonary parenchyma. (A): Diffuse lesion characterised by a total absence of inflammatory response with a severe destruction of the bronchoalveolar structures (black star: bronchiole; white star: pulmonary artery). (B): Severe parenchyma colonisation by the fungus with infiltration of bronchioles (black star) as well as pulmonary arteries (white star). (C): Destruction of the bronchiolar (black star), alveolar, and vascular (white star) walls by hyphae. (D): Branched mature hyphae were observed, displaying a high infiltrative potential. A, C: HE staining; B, D: GMS staining.