Rare occurrence of bilateral breast and peritoneal metastases from osteogenic sarcoma

Breast metastases are uncommon and typically spread from contralateral breast carcinomas. Breast metastases that spread from extramammary malignancies are even less common, and account for 0.5%-6.6% of all malignant breast disease. As extrapulmonary metastases from osteosarcoma are uncommon, breast metastasis from osteosarcoma is extremely rare. We report a case of breast and peritoneal metastases from a tibial osteosarcoma 18 months after diagnosis, and 9 months after surgery and adjuvant chemotherapy. Computed tomography findings of multiple calcified and noncalcified tumour deposits in the lungs, pleura, peritoneum, chest wall and both breasts are described.