Biological characterization of human bone tumors. VII. Detection of malignancy in a giant cell tumor of bone by flow cytometric DNA-analysis.

The biological behavior of giant cell tumors of bone often cannot be definitively evaluated by light and electron microscopical criteria. As DNA aneuploidy was found to be a highly sensitive marker of malignant cells, we have analyzed this descriptive parameter in 4 giant cell tumors of bone by flow cytometry. Three of the four cases were non-metastasizing giant cell tumors, the fourth was a clinically malignant neoplasm presenting extensive visceral metastases four years after first diagnosis. Neither light- nor electron microscopical findings provided unequivocal criteria for defining the biological dignity of the four tumors. DNA aneuploidies were identified in the metastasizing case only, whereas the three clinically benign tumors showed a unimodal euploid DNA distribution. Thus flow cytometric DNA analysis is an additional diagnostic tool for the detection of malignancy in giant cell tumors of bone.