Mandibular Osteosarcoma Presenting as a Benign Odontogenic Lesion: A Case Report

Background Osteosarcoma of the jaws (OSJ) is a rare malignant bone tumor with variable clinical and radiographic presentations, often mimicking benign odontogenic or inflammatory lesions. This diagnostic uncertainty frequently leads to delayed recognition and treatment. Case A 29-year-old female presented with a gradually enlarging, painful swelling in the left mandibular region that had been progressing over 3 months. The swelling was associated with tooth mobility. She had previously received treatment for a presumed periapical pathology elsewhere. On radiographic evaluation, including intraoral periapical and occlusal radiographs, orthopantomogram, and cone-beam computed tomography, an ill-defined mixed radiolucent–radiopaque lesion was observed, along with widening of the periodontal ligament space and a characteristic sunburst periosteal pattern. Histopathological analysis revealed a highly cellular malignant neoplasm composed of pleomorphic osteoblast-like cells producing disorganized woven bone, leading to a diagnosis of well-differentiated osteogenic sarcoma of the mandible. Discussion OSJ presents significant diagnostic challenges due to its rarity and overlap with common dental conditions. Correlation of clinical features with advanced imaging and histopathology is essential for early diagnosis. Conclusion This case emphasizes the need for heightened clinical suspicion when evaluating atypical jaw lesions. Prompt multidisciplinary diagnosis and management are essential to improve outcomes in patients with OSJ.