45. Aspergillosis of the lung

Staining: PAS

Organ: Lung

Description:

On the lower right corner of a slide we can see an artery filled with PAS-positive rod-shaped fungi.

On the middle of the slide we can find necrotic debris inside alveoli.

On the top of the slide we can find normal lung parenchyme. Anthracosis is present.

Diagnosis: Aspergillosis of the lung

Etiology:

• Immunocompromised patients

Theory:

This slide shows a case of necrotizing pneumonia secondary to infection by the fungus aspergillus. The fungi themselves have PAS positive cell walls and can be seen in the artery in the lower right corner.

The fungi have septa/hyphae that are PAS positive also, as seen on the figure below.

Overview. It looks like an angry hen.

Close-up of the fungi inside the artery. Those transverse PAS-positive things inside the fungi are septa or hyphae. Note how it’s the cell wall of the fungi that is the most PAS positive

Here you can see the necrotizing pneumonia. Note how there is necrotic debris inside the alveoli