Final answer:
Churg-Strauss syndrome on histology shows inflammatory events caused by immune complex accumulation in small blood vessels, peripheral and tissue eosinophilia, and the presence of granulomas. There might be a smear containing Pneumocystis jirovecii.
Step-by-step explanation:
On histology, Churg-Strauss syndrome, also known as eosinophilic granulomatosis with polyangiitis (EGPA), shows certain characteristic findings. A significant characteristic is the inflammation of small blood vessels, resulting from the formation of small immune complexes that deposit on the surface of the epithelial cells lining the inner lumen of these vessels. This immune complex accumulation leads to inflammatory events.
Additionally, there may also be peripheral and tissue eosinophilia, a condition in which there is a high level of eosinophils, a type of white blood cell. Figure 22.12 provides a basic example of this as it shows lung tissue during an asthma attack exhibiting thickened mucosa, increased mucus-producing goblet cells, and eosinophil infiltrates.
Another characteristic is the presence of granulomas, which are nodules that signify chronic inflammation. A smear containing Pneumocystis jirovecii, a fungus often associated with immunosuppressive conditions, including Churg-Strauss syndrome, might be found as well.
Learn more about Churg-Strauss syndrome histology