Morphological typing of chondrosarcoma: a study of 94 cases.

Ninety-four chondrosarcomas of the Hamburg Bone Tumour Registry were reviewed in a retrospective study. The purpose of this study was to examine the morphological characteristics of different types of chondrosarcomas and to describe distinctive features of location, the age distribution and the male to female ratio. Central chondrosarcomas can be divided into classical chondrosarcomas, dedifferentiated chondrosarcomas, mesenchymal chondrosarcomas and clear-cell chondrosarcomas. Five periosteal chondrosarcomas were represented. Classical chondrosarcomas and clear-cell chondrosarcomas show a significant predominance of males; no sex predilection was seen in dedifferentiated and mesenchymal chondrosarcomas. Nearly 60% of classical and mesenchymal chondrosarcomas occur in the trunk. Eighty-five percent of dedifferentiated chondrosarcomas are located in the long bones of the limbs. Clear-cell chondrosarcomas arise in the proximal part of the femur. There is a marked predilection for mesenchymal chondrosarcomas in the second and third decades of life. The average age of patients with classical chondrosarcomas was 54 years, but clear-cell chondrosarcomas occur 10 years earlier and dedifferentiated chondrosarcomas 10 years later. Characteristically, classical chondrosarcomas produce a pure chondroid matrix with variable differentiation of tumour chondrocytes. The most important histological feature of the defifferentiated chondrosarcoma is the close association of two different cellular components. One of these consists of cartilage, which is generally well differentiated. In most of our cases the second component showed features of osteosarcoma (50%). Mesenchymal chondrosarcoma is characterized by concentric infiltration of cartilage islands by small tumour cells. Clear-cell chondrosarcomas show regions of cartilaginous tumour and areas of closely packed, glycogen-rich, large tumour cells with distinct boundaries. Osteoid formation and multinucleated giant cells are present in clear-cell areas. Knowledge of this group of tumours is indispensable for correct histological diagnosis and typing and is important in the design of surgical therapy and the prediction of biological behaviour.