Secondary chondrosarcoma. Four cases and review of the literature.

The authors present four new cases of chondrosarcoma secondary to multiple osteochondromatosis (MOC). As MOC is a familiar and hereditary condition, the patients should be evaluated throughout their lives, from childhood to adulthood. Because of the risk of malignant transformation in this condition, any adult patient complaining of pain and excessive increase in tumor size should be investigated for sarcomatous degeneration. Wide resection, when possible, must be the elected treatment in this type of patient, in order to avoid the risk of local recurrence.