Intraoperative cytology of osseous lesions.

Cytologic preparations were made from 53 biopsies of osseous and related lesions submitted for intraoperative diagnosis. Smears made by scraping the surface of the lesion and spreading the material obtained on a glass slide were most commonly used. These preparations were found to be valuable adjuncts to frozen sections because cytologic details were so much more clearly visible. Among specific diagnostic features found to be particularly helpful were the large numbers of nuclei found in most of the multinucleated cells from giant-cell tumors but in few osteoclasts from other lesions; the metachromatic staining of osteoid in air-dried, Romanowsky-stained smears from osteosarcomas; and the ease with which multinucleated cells can be identified in smears from chondrosarcomas. The characteristic appearance of chondroblasts from a chondroblastoma; the distinctive appearances of osteoclasts and multinucleated histiocytes from eosinophilic granulomas; the unique appearance of synovial cells from pigmented synovitis; and the ease with which small cells of a metastatic carcinoma could be distinguished from hematopoietic bone-marrow cells were other significant findings. These and other features of the lesions encountered are presented in greater detail.