We report a case of a 13-year-old girl with an osteosarcoma of the right humerus, which had been diagnosed as an aneurysmal bone cyst at our institution. She underwent curettage and bone grafting of the lesion, which resulted in implantation metastasis of the tumour to the ilium. She died 15 months after presentation owing to pulmonary metastases. This report highlights the possibility of metastasis occurring by direct implantation to a graft donor site. We strongly recommend that a biopsy be performed in cases of presumed benign lesions before proceeding with the definitive surgery.
