[Cartilage tumors. Classification, conditions for biopsy and histologic characteristics]

Primary cartilage-forming tumors of the bone are a large group among the rare bone tumors. The clinical and radiographic findings of the different entities show similar findings. Bone biopsy is still the most relevant examination in the final diagnosis of the lesion. The requirements for a correct biopsy and the main features of the macroscopic and histologic findings of cartilage tumors are presented from the viewpoint of the pathologist. Differentiation between benign enchondroma and grade I chondrosarcoma requires close interdisciplinary cooperation to avoid over-treatment and relapse. Rare low-grade malignant cartilage tumors such as clear-cell chondrosarcoma need to be diagnosed in specialized centres to arrive at the correct therapy. The morphologic features of mesenchymal chondrosarcoma, clear-cell chondrosarcoma and secondary chondrosarcoma in osteochondroma are demonstrated. The aim is to correlate the morphologic and radiographic features. The same applies to benign entities such as osteochondroma, chondroblastoma and chondromyxoid fibroma.