Atypical spindle cell osteosarcoma in the diaphysis and proximal epiphysis of the tibia: clinical case report. Rev. Invest. Univ. Quindío [Internet]. 2023 Apr. 5 [cited 2026 Jun. 25];35(1):36-42. Available from: https://revistas.uniquindio.edu.co/ojs/index.php/riuq/article/view/898