There are many classification systems for grading osteosarcoma. One of the widely used system is the 4-tiered (Broder's) system based on the percentage of anaplasia in the tumor. Majority of the conventional central osteosarcomas fall in grade 3 or grade 4 category. The tumors assigned grade 1 are low-grade central osteosarcomas and the usual parosteal osteosarcomas. Osteosarcomas of the jaw often tend to show grade 2 histology. The image shows a focus of grade 4 osteoblastic osteosarcoma.