Cyto-histological correlations in primary, recurrent, and metastatic bone and soft tissue osteosarcoma. Institut Curie's experience

To determine diagnostic cytomorphologic features of osteosarcoma on fine-needle aspiration materials, we reviewed the cytologic material and corresponding histologic slides of 126 tumors in 107 patients. Fifty-five (43.6%) tumors were primary, 31 (24.6%) were recurrent, and 40 (31.8%) were metastatic. Review of original cytology reports revealed that 120 (95.3%) tumors were diagnosed as malignant. Six (4.7%) cases were reported as suspicious, false-negative, or unsatisfactory samples. Our findings showed that osteoblastic roundish cells, spindle-shaped cells, reactive giant cells, and osteoid were the most consistent features representative of osteosarcoma. Periosteal reactions, fractures with callous formation, giant cells of osteoclastic type in various conditions, chondrosarcoma with enchondral ossification are entities to consider in the differential diagnosis.