Chondroblastic Osteosarcoma of the Mandible: An Uncommon Site for Osteosarcoma

Osteosarcoma is one of the most common types of malignant bone tumors, typically involving long bones such as the femur, tibia, and humerus. However, osteosarcomas occurring in the jaws are exceptionally rare, accounting for approximately 7% of all osteosarcoma cases and just 1% of malignancies in the head and neck region. This type of tumor usually affects individuals in their second and third decades of life. The subtypes of osteosarcoma include osteoblastic, chondroblastic, fibroblastic, small cell, and epithelioid. Chondroblastic osteosarcoma is associated with a poor prognosis, marked by a high recurrence rate, metastatic potential, and poor long-term survival outcomes.

Here, we present the case of a 65-year-old woman with a painless swelling over the left cheek for 1 year, which significantly increased in size over the past 3 months, accompanied by trismus, reduced oral intake, and weight loss. Examination revealed a non-tender, hard swelling on the left cheek measuring 20x20cm, with prominent dilated veins. The left external auditory canal was collapsed due to the mass effect. Histopathological examination resulted as chondroblastic osteosarcoma of the left mandible. Computer tomography showed a large lobulated enhancing mass occupying the left cheek, associated with bone erosion and an aggressive periosteal reaction resembling a 'sunburst' pattern involving the ramus extending to the angle of the left mandible. The patient undergone open tracheostomy, left temporary tarsorrhaphy, wide local excision of tumor, left hemimandibulectomy, left partial maxillectomy and anterolateral thigh free flap reconstruction as patient unable to tolerate neoadjuvant chemotherapy.