Microscopic: All alveolar spaces of the involved lobe contain neutrophiles (contrast with viral pneumonia in which the alveolar septa contain lymphocytes). The bronchioles also are inflamed and have a neutrophilic infiltrate in their walls and lumina. After complete resolution, the underlying lung architecture is preserved.
Legends:
A94-15: This gross photograph of a cut lung shows consolidation and discoloration of most of the lower lobe (red hepatization).
A90-13: This low power photomicrograph shows many alveolar spaces filled with inflammatory infiltrate.
A90-13: This high power photomicrograph shows the infiltrate to be composed of neutrophiles. Note that the alveolar septa are relatively normal.