giant cell tumour BrE
giant cell tumor AmE
gigantocellular tumour BrE
gigantocellular tumor AmE

This led to the discovery of cellular and molecular mechanisms of pathological bone resorption associated with primary and secondary bone tumours, particularly breast cancer metastasis, Ewing sarcoma and giant cell-rich lesions such as giant cell tumour of bone and pigmented villonodular synovitis.