Multinucleate foreign-body giant cell formation.

The formation of multinucleate giant cells (MGCs) was studied after the subcutaneous implantation of cellophane foil into 25 Wistar rats. Epitheloid cells fuse to form MGCs of the Langhans type, with nuclei at the cell periphery that later migrate to the central cell region (Touton's type). Both cell types fuse again to form the monstrous MGC (more than 1 mm in diameter) widely extended on the implant surface. These cells are characterized by enlarged nuclei which are significantly larger than those in MGCs of the Langhans type. The positivity of widely extended MGCs for acid phosphatase and sodium tetrazolium reductase seems to be lower than that in Langhans' or Touton's cells. Widely extended MGCs cover a large area of implant surface and represent a barrier-like structure which separates the surrounding tissues from foreign bodies or materials that cannot be eliminated or disintegrated.