The ultrastructure of nuclear inclusions in the giant-cell tumor of bone

The ultrastructural study of three cases of giant-cell tumor of bone showed two types of nuclear inclusions. The first type, common to giant cells and stromal cells was granular, and sometimes associated with a fibrillar pattern observed only in giant cells. The second type was represented by nuclear bodies, encountered mostly in the stromal cells. The nuclear bodies were made up of a granular core enveloped in a multilayered coat. The nature of these nuclear inclusions might be viral and thus a viral pathogenesis of the giant-cell tumor of bone is discussed.