Osteosarcoma is the most common primary malignant bone tumor, predominantly occurring in long bones and
occasionally in the maxillofacial region. In the maxillofacial region, approximately 5% of OS starts in maxillary
bones while the mandible is the most involved site. OS of the maxilla usually involves adults with ages ranging
between the third and fourth decades of life. In addition, metastasis are rare and the prognosis is significantly
better when compared to its counterpart in long bones. However, the World Health Organization (WHO) listed
several variants that differ in location, clinical behavior and level of cellular atypia. The conventional or classical
osteosarcoma is the most frequent variant, which develops in the medullary region of the bone and can be
subdivided in osteoblastic, chondroblastic and fibroblastic histological types, depending on the type of extracellular matrix produced by tumour cells. The aim of this literature review is to provide information about
osteosarcoma for further education in this field
Key words: Osteosarcoma, WHO, Classification