The histologic hallmark is lymphangitic distribution of non-caseating granulomas with Langhans' or foreign body type giant cells
Within the granulomas there may be calcified, rounded, laminated concretions known as Schumann's bodies
With the giant cells there are often star-shaped inclusions (Asteroid bodies)
The above 2 are characteristic, but not diagnostic, of sarcoidosis
There is varying degree of fibrosis around granulomas and in the interstitium
Sarcoidosis is a diagnosis of exclusion