Slide 1 (28000-D0552)
Aspergillus species may infect abnormal airways (e.g. old tuberculous of bronchiectatic cavities) and remain non-invasive. In immunocompromised patients, however, this fungus may invade the lung parenchyma, causing a severe, often necrotizing, pneumonia. In this section, taken from the lung of an organ transplant patient, the bronchial lumen is virtually filled by a mass of fungal hyphae.

Slide 2 (28000-D0552)
Higher power: Note the hyphae invading the bronchial wall.