Figure 4. Invasive pulmonary aspergillosis in a 55-year-old female patient with chronic myeloid leukaemia. A magnified view of a slice of the right upper lobe shows vital hyphae of Aspergillus fumigatus in a pulmonary lesion with central necrosis. In the periphery of the lesion, beneath the "crescent air", a rim of chronic inflammation is present (black arrow). Note also hyphae in intravascular thrombotic material (white arrow). (a) PAS x 5. (b) Photomicrograph from the area of consolidation shows tissue necrosis. Aspergillus fumigatus hyphae could be identified in necrotic tissue (white arrow). PAS x 400.