Juxtacortical chondromyxoid fibroma in the small bones: two cases with unusual location and a literature review

Chondromyxoid fibroma is a rare bone tumor of cartilaginous origin, representing less than 1% of all bone tumors. It preferentially arises in the eccentric location of the metaphysis of a long tubular bone. Juxtacortical locations are reported infrequently in the long bones and even more rarely in short tubular bones, with only three cases documented. Here we present two new cases of juxtacortical chondromyxoid fibroma in the small bones. One was an intracortical osteolytic lesion of the metatarsal bone of the foot with degenerative atypia that histologically should be differentiated from chondrosarcoma. The other was a phalangeal mass protruding into the interphalangeal joint of the hand, which had been labeled mistakenly as a soft tissue mass preoperatively. These cases illustrated that chondromyxoid fibromas have various the manifestations and should be included in the differential diagnosis of an osteolytic lesion or an exophytic mass in the small bones.