Chondrosarcoma, Grade I
Grade I chondrosarcoma arising in a metacarpal bone in a 69 y/o male. Distinction between a low-grade chondrosarcoma arising in the small bones of hands and feet from enchondromas can be quite challenging. Enchondromas in this location can be quite cellular; however, they form well-circumscribed nodules which grow by expansion. Chondrosarcomas, on the other hand, tend to grow by permeation of the marrow spaces and entrapping the bony trabeculae. For a cartilagenous tumor arising in the small bones of hands and feet, permeation of the surrounding soft tissue (as seen in this image) is considered diagnostic of chondrosarcoma.