[Tubular filamentous intranuclear inclusions on multinucleated cells of bone giant cell tumors].

Electron microscopy revealed tubular filamentous inclusions within nuclei of giant cells in 22 per cent of 31 cases of genuine giant cell tumours of bone. These inclusions are, both on biopsy and on culture, similar to those of osteoclasts of Paget's disease but less constant, less numerous and mainly intranuclear. Controls by the study of giant multinucleated cells from osseous and extra osseous lesions were negative.