Hereditary multiple exostoses with malignant transformation


Malignant degeneration of an osteochondroma in patients with hereditary multiple exostoses is the most feared complication of the disease. When osteochondromas become malignant, the cartilaginous cap is the part that transforms most often into chondrosarcoma, as is the case in this patient. This patient also reported that he had multiple family members with bony bumps, illustrating the autosomal dominant inheritance pattern of the disease.