C-ERB B-2 STAINING IN PRIMARY SYNOVIAL CHONDROMATOSIS - A COMPARISON WITH OTHER CARTILAGINOUS TUMORS

In this study C-erb B-2 immunostaining has been used to highlight dist inct differences between the cartilage found in primary synovial chond romatosis (n=20), normal articular cartilage (n=10), benign enchondrom as (n=10), and chondrosarcomas (n=10). There was no positive staining in either the normal cartilage or the chondromas, but 15 cases of syno vial chondromatosis showed at least some staining, although in the maj ority of cases fewer than 50 per cent of cells stained positive. There was no correlation between cellularity/ pleomorphism and the extent o r intensity of staining. Five of the chondrosarcomas were positive, wi th more than 50 per cent of cells showing positive staining in three o f these cases. All positive cases in this series showed a diffuse cyto plasmic staining pattern. Despite these results, there was no Ki-57 po sitive staining in synovial chondromatosis, which tends to suggest tha t the demonstrated expression of C-erb B-2 is not related to prolifera tive activity. The significance of this staining remains undetermined.