Soft tissue implantation of chondromyxoid fibroma.

While chondroblastoma, a usually benign cartilaginous bone tumor that has histologic features in common with chondromyxoid fibroma, can invade or be accidentally implanted in the soft tissues, it is less well known that this may also occur with chondromyxoid fibroma. A patient is described in whom a chondromyxoid fibroma recurred in the superficial soft tissues following prosthetic replacement of the upper femur. This is only the second such case reported without a simultaneous recurrence within the adjacent bone. The close association of the soft tissue tumor with suture fragments is taken as evidence for implantation at the time of operation. A unique histologic feature was the presence of vascular invasion within the implant. The literature on soft tissue involvement by chondromyxoid fibroma is reviewed and the meaning of this in terms of malignancy is discussed.