Interstitial Pneumonia

Churg-Strauss syndrome

At low power, small granulomatous foci appear around small- to medium-sized arteries and veins. The multinucleated giant cells are indicated by the dark spots (arrow).

Here, one of the granulomatous foci shows fibrosis and chronic inflammatory cells including a number of eosinophils. The arrow indicates a multinucleated giant cell. The asterisk is in the center of a zone of necrosis--a so-called eosinophilic abscess.

A medium-sized pulmonary artery has a destructive angiitis. The inflammatory cells in the intima, media, and surrounding tissue are mainly eosinophils. The arrows mark the media of the vessel.

Summary of findings in Churg-Strauss syndrome

Eosinophilic pneumonia

Consolidation of lung parenchyma with mild alveolar wall thickening is part of Churg-Strauss syndrome, but similar changes occur in eosinophilic pneumonia of any type and in allergic bronchopulmonary aspergillosis.

Note that the alveoli are filled with a mixture of macrophages and eosinophils. Alveolar walls are variably inflamed.