*2.7.1.3 Coccidiosis*

*Coccidia* most often lead to necrotizing granuloma formation; the eosinophilic reaction may be marked or absent; numerous neutrophils may be observed. Like in other infections, granulomas are located peribronchiolar or with destroyed bronchioles. This process is accompanied by the formation of small non-necrotizing granulomas at the periphery. *Coccidia* are usually found in the center of necrotizing granulomas, they consist of large spherical structures (spherules) containing yeast-like structures (endospores). Endospores of various sizes can be located in necrosis or cellular debris, resembling other fungal infections. The detection of spherules and endospores favor the diagnosis of coccidiosis. Like *Histoplasma, Coccidia* do not grow in vitro; thus, the diagnosis can only be made by histological examination [15].

**57**

*Pathology of Sarcoidosis and Differential Diagnostics of other Granulomatous Diseases*

Blastomycosis is a rare disease, and this diagnosis may be suspected when granulomatosis or giant cell lesion in combination with severe acute inflammation is detected. Blastomycosis is characterized by basophilic necrosis rich in cellular debris in contrast to eosinophilic or slightly "dirty" infectious necrotizing granulomas. Blastomycosis is often a bronchiolocentric process. Large, thickwalled, yeast-like *Blastomyces* cells can be detected in H&E and also mucicarmin staining. Active budding is a distinctive feature of the microorganism; nuclear material (multiple nucleoli) can also be found inside the cells, but these signs are not always observed. In this regard, compared to *Histoplasma* and *Cryptococci* cells and *coccidial* endospores, *Blastomyces* cells are larger but still smaller than *coccidial*

Most pathologists are familiar with the conventional picture of pneumonia caused by *Pneumocystis*, but 5–17% describe the formation of an ill-defined

intraalveolar epithelioid or histiocytic granuloma around the eosinophilic exudate, sometimes without exudate; the formation of well-defined granulomas with central necrosis or without it is also possible [16, 17]. Sometimes the granulomatous reaction in pneumocystis pneumonia is a foreign-body granulomatosis (**Figure 13**).

*Dirofilaria* is one of the most common parasites that lead to the granulomatous inflammation in lungs. This nematode infects dogs more commonly, but the disease can also occur in humans, as the infection is transmitted through an insect bite; the larva enters the right heart and into the pulmonary arteries during embolism, causing thrombosis of the latter with an infarct-like necrosis development (**Figure 14**). In one-third of the cases, granulomas are formed in the adjacent lung

*DOI: http://dx.doi.org/10.5772/intechopen.90693*

*2.7.1.4 Blastomycosis*

*Necrotizing granuloma fragment with cryptococci cells. H&E.*

**Figure 12.**

spherules [15]*.*

**2.8 Parasites**

*2.7.1.5 Pneumocystosis*

*Pathology of Sarcoidosis and Differential Diagnostics of other Granulomatous Diseases DOI: http://dx.doi.org/10.5772/intechopen.90693*

**Figure 12.** *Necrotizing granuloma fragment with cryptococci cells. H&E.*
