Osteosarcomas are malignant neoplasms of the bone which commonly affect the long bones. The involvement of the jaws are rarely noticed. These neoplasms often shows a typical clinical behaviour as well as varied radiological appearances. Similarly, their histological growth pattern can be quite diverse. Confirmation of the final diagnosis of an osteosarcoma often requires a histopathological examination of the multiple biopsy specimens and vigorous discussion amongst the experts. All these clinical features, radiographic appearances and histological diagnostic difficulties were encountered in a case of osteosarcoma of the mandible in a 29-year old female.

Osteosarcoma (OS), which is sometimes referred to as osteogenic sarcoma, is the most common primary bone tumour in adolescents and young adults. Mandibular and maxillary osteosarcomas account for 6% to 9% of all the osteosarcomas. Mandibular OS is often considered as a distinct entity because of its predilection to older patients (mean age: 34 to 36 years). The WHO has recognized several variants of OS that differ in location, clinical behaviour, and the degree of cytologic atypia. The most frequently occurring variant is the classical osteosarcoma which arises centrally within the bone . It is a tumour that can occur in any bone but which most commonly occurs in the long bones of the extremities, near the metaphyseal growth plates. Osteosarcomas accounts for about 20% of all the sarcomas and about 4%-6% occur in the maxillofacial region. Sometimes, they are referred to as gnathic osteosarcomas. The purpose behind writing of this case report was to highlight the diagnostic difficulties encountered in a patient of OS which affected the mandible and presented as a swelling in the lower right third molar region.