Karl Touton and his "xanthelasmatic giant cell." A selective review of multinucleated giant cells.

The position of the Touton giant cell in relation to the foreign body and Langhans type of giant cell is considered. (A short account of Karl Touton's life is also included.) After reviewing the historical development of the concept of giant cells and current interpretations of their nature, the unitarian view of polykaryons now favored by workers in the field is extended to include also the "xanthelasmatic giant cell" of Touton, whose characteristic appearance is determined merely by the presence of demonstrable lipid in the cytoplasm. It is proposed that Touton cells develop when the stimulus to cell fusion is accompanied also by a factor stimulating lipid uptake. This factor is missing in the development of the other two giant cell "types," but apart from that there are no other significant differences.