Osteosarcoma of Jaw with Varying Histomorphologic Patterns: Case Report

INTRODUCTION: Osteosarcoma is a malignant mesenchymal tumor whose cancerous cells produce osteoid matrix. It is a common primary malignant bone tumor, representing 23% of total head and neck malignancies. Osteosarcomas of the jaws are rare lesions, representing only 4-7% of all osteosarcomas. This presentation discusses the clinical, radiographical, and histopathological features of a case of osteosarcoma of the mandible with unusual histopathological appearance. CASE REPORT: A 21-year-old male patient reported with a diffuse swelling of the right side of mandible with dull ache and increasing difficulties with eating and speech. Incisional biopsy done showed a histopathological picture of osteosarcoma and osteoblastoma. Hemimandibulectomy was done and the histopathology showed varying patterns of the lesion-like osteoblastoma-like osteosarcoma and osteoblastic variant of osteosarcoma. Focal areas in the lesion also showed fibrohistiocytic differentiation which may be mistaken for malignant fibrous histiocytoma. Hemangiopericytomatous appearance was also seen. Hence, it was necessary to differentiate between all the lesions as the treatment plan for all these lesions is different. Rarely, tumor may show a spectrum of histopathology as seen here in a case of osteosarcoma of the mandible. CONCLUSION: The treatment plan and prognosis for each type of these lesions are different. Thus, thorough histopathological evaluation will help in accurate diagnosis, proper treatment planning, and prognosis of these lesions.