Chondroblastic osteosarcoma.

The purpose of this paper is to report a case of chondroblastic osteosarcoma in the region of the maxilla, with 5 months of evolution. The term osteosarcoma refers to a heterogeneous group of malignancies with bone formation or mesenchymal tissue with histopathological evidence of osteogenic differentiation. The pattern of chondroblastic osteosarcoma represents 25% of all reported cases of this neoplasm. Its histopathological diagnosis is based on the predominance of a chondroid matrix formed in the midst of neoplastic cells. A woman patient, 27-year old, melanoderm, presented on extraoral exam with facial asymmetry caused by the a swelling in the premaxillary region with upper lip protrusion. Intraoral exam showed a maxillary tumefaction with involvement of the vestibular and palatine regions. The computerized tomography (CT) analysis exhibited a radiolucent mass with dispersed areas of radiopacity, with poorly defined and indistinct peripheral edges. The patient was subjected to incisional biopsy and histopathological examination showed the presence of a malignant neoplasm of mesenchymal origin characterized by the presence of irregular bone trabeculae dispersed among mildly atypical chondroblastic cells. The World Health Organization (WHO) recognizes several variants that differ in location, clinical behavior and degree of cellular atypia. The conventional or classical osteosarcoma is the most frequent variant, which develops within the medullary bone. This report illustrates the rapid evolution of one of the histological variants of osteosarcoma.