RESUMO
Mesenchymal chondrosarcoma is an infrequent malignancy of bone and soft tissue, characterized by its peculiar bimorphic histological pattern. The use of fine-needle aspiration (FNA) in the diagnosis of bone tumors is controversial. A 31-year-old woman presented with a mandibular lesion detected on routine examination for orthodontic treatment. Radiography revealed an ill-defined mixed radiolucency in the premolar region of the right mandible with invasive characteristics such as root resorption and widening of the periodontal ligament space of neighboring teeth. Blood clots obtained at FNA were fixed in formalin and exhibited spindle cells surrounding islands of pleomorphic chondroblasts against a bloody background. Histopathologically, clusters of spindle cells juxtaposed with mesenchymal tissue were detected, with a large hemangiopericytomatous component. In the present case, cytological findings combined with clinical and radiological data provided valuable information in establishing the diagnosis of malignancy and in planning further procedures and treatment.
