[Ultrastructure of a giant cell tumor of the bones and of osteogenic sarcoma].

A comparative electrone microscopic investigation of osteogenic sarcomas and giant-cell bone tumors has revealed the ultrastructural differences between a mononuclear component of the giant-cell tumor and the most frequently observed type of osteogenic sarcoma cells (a well-developed ergastoplasma in cells of osteogenic sarcoma and moderately developed one- in the giant-cell tumor of bones, different rate of development of the mitochondrial apparatus, the character of nuclei) that indicates different genesis of these two tumor types. In giant-cell bone tumors a definite ultrastructural similarily between some mono- and multinuclear cells (a large number of mitochondrial, similar character of nuclei) may speak in favour of the common source of their development and explains the high activity of oxidoreduction enzymes in them revealed histochemically.