Malignant degeneration of a chondromyxoid fibroma in a child.

A 10-year-old boy was treated for a chondromyxoid fibroma of the left femur by curettage, and 2 months later complete healing was demonstrated radiographically. Three years after operation, radiographs revealed replacement of the ilium, ischium and upper femur, and destruction of the left hip by a soft-tissue and bony mass; a left hemipelvectomy was performed for what was shown to be a chondrosarcoma. Follow-up 10 years after the initial operation and 7 years after the hemipelvectomy has confirmed uneventful recovery in this rare case of malignant degeneration of a proven chondromyxoid fibroma of bone.