Bursa formation in secondary chondrosarcoma with intrabursal chondrosarcomatosis.

Osteocartilaginous exostoses (osteochondromata) are rather common bone tumors. Although most are straightforward lesions, one may occasionally encounter one of a number of well-recognized complications. In the current case, secondary malignant transformation and bursal sac formation were present. Additionally, numerous malignant chondroid nodules were shed into the attached bursa, giving rise to a large soft tissue mass, a situation which we feel is both remarkable and, to our knowledge, unique.