A rare case of calcified metastasis in a patient with primary osseous Ewing's sarcoma.

We report an unusual case of an 11-year-old male with Ewing's sarcoma of the right fibula who presented 6 years post-remission with progressive dyspnea, fever, and swelling of the right ankle. Imaging revealed multiple partially calcified "cannonball" pulmonary metastases and a large, partially ossified, pleura-based mediastinal mass-an atypical metastatic presentation for this tumor. Histopathological confirmation was essential due to the diagnostic challenge posed by the calcifications, which are typically associated with infection or other malignancies. This case highlights the importance of considering atypical metastatic presentations in Ewing's sarcoma and emphasizes a multimodal diagnostic approach. The findings contribute to the sparse literature on calcified metastases in Ewing's sarcoma, calling for further research to understand the mechanisms and clinical significance of such presentations.