Histopathologic image of aspiration pneumonia in an elderly patient with debilitating neurologic illness. Note foreign-body giant cell reaction. Autopsy case. H & E stain.
A foreign-body giant cell is a collection of fused macrophages (giant cell) which are generated in response to the presence of a large foreign body. This is particularly evident with implants that cause the body chronic inflammation and foreign body response. This reaction to the implant causes damages to the infected area, leaving the exterior surface with scars. 
The nuclei are arranged in a disorganized manner. The nuclei in this cell are centrally placed and overlap each other.  This is in contrast to a Langhans giant cell, where the nuclei are arranged on the border.
Foreign body cells can detect and eliminate bacteria caught with in the body, by sensing the unique sugar coating that are on the invading prokaryotes. These macrophage cells are one of a few phagocytic cells, but not the first to come to an injury site, and tend to linger from anytime between days to weeks. There has been some research done on other variations of giant calls with different functions.