The
DNA content of
osteosarcomas, and of
giant cell tumors,
osteoblastomas,
aneurysmal bone cysts, and fibrous dysplasias was determined by cytophotometry. Of 158
tumors, 141 were histologically noncontroversial, whereas 17 posed diagnostic difficulties. In the noncontroversial group, all 41 benign
tumors had a diploid (normal)
DNA content. Ninety-two of 96 high-grade
osteosarcomas were hyperploid (increased
DNA content). The four analyzed low-grade parosteal
osteosarcomas were diploid. Among 17 diagnostically controversial cases, nine were primarily diagnosed and treated as benign. Three of these patients, nevertheless, exhibited a malignant
clinical course and two had local recurrence. All five proved to have hyperploid
tumors. The four nonrecurrent lesions were diploid. Of eight patients primarily evaluated as malignant, one died and two developed local recurrence. These three patients had hyperploid
tumors. Among the five nonrecurrent lesions, two were hyperploid and three diploid. In the diagnostically controversial group, recurrence or death was consistently related to hyperploidy. The present study shows that the vast majority of high-grade
osteosarcomas are hyperploid. Benign bone
tumors, which may be mixed up histologically with
osteosarcoma, are diploid. Routine
DNA analysis of primary bone
tumors, as an adjunct to histopathologic assessment, can be employed to obtain diagnostic confirmation. In cases presenting histopathologic difficulties, ploidy determination may provide decisive diagnostic information.