Primary osteosarcoma of the talus.

Osteosarcoma OS of the talus is extremely rare, and few cases have been reported in the literature. We present a case of a 33-year-old male with painful swelling of his left ankle joint. He underwent several radiological diagnostic modalities that showed osteolytic lesion in the posterior aspect of the left talus associated with new bone formation projecting from the posterior-medial aspect of that bone. His chest x-ray showed multiple rounded lung metastases, some of them showed calcifications. Open biopsy was performed. The histopathology confirmed the diagnosis of osteoblastic OS of the talus.