Histologic Changes

This section is from the pale, partly consolidated area of lung. It shows an interstitial pneumonia that tends to spare the alveolar spaces. Alveolar walls are thickened, infiltrated by chronic inflammatory cells, and have hyperplastic type II cells.

The pneumonia has caused considerable shrinkage of the involved lobules, but spares a lobule located at the lower left. Note the thickening of the interlobular septum that separates the upper two lobules. The pleura is hyperemic, but otherwise normal.

At higher magnification of the section shown above, loose granulation tissue can be seen widening the alveolar walls. The type II epithelial cells, which are hyperplastic, are mostly detached from the alveolar walls, a postmortem change.

The changes shown here are mostly reversible because there is little collagen deposition. However, despite steroid therapy for 6 days, resolution did not occur.

Clinical summary Image 5

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