Slide A
Sarcoid granulomas are typically compact aggregates of epithelioid histiocytes, with variable numbers of lymphocytes and giant cells. There is usually no central necrosis.

Slide B
The giant cells of granulomas may contain a variety of inclusions, such as calcium oxalate crystals. This section shows a giant cell with an "asteroid body," which ultrastructurally consists of microfilaments and microtubules. It is thought that these peculiar structures result from reorganization of the cytoplasmic framework of the histiocytes when they fuse into giant cells.