Complex cytogenetic aberrations in a well-differentiated chondrosarcoma.

The cytogenetic analysis of a well-differentiated (grade I) chondrosarcoma is presented. Despite a low-grade histopathology, metaphase preparations of tumor cells were characterized by numerous structural chromosome aberrations and a striking degree of genetic instability; the t(9;22)(q31;q12) that has been described recently in extraskeletal myxoid chondrosarcoma was not observed. This report suggests that chondrosarcomas may be heterogeneous cytogenetically. In chondrosarcoma, it appears that "high-grade" cytogenetic abnormalities do not necessarily engender a high-grade histology. These findings offer a possible explanation for the clinical aggressiveness of certain low-grade chondrosarcomas.