Giant cell tumor of bone: a report of two cases with metaphyseal lesions and their progression to the articular surface.

Two patients presented to outside providers with joint pain. Both had isolated lytic metaphyseal lesions on plain radiographs that were not noted or acted upon. Subsequent radiographs showed large expansile lytic lesions involving the metaphysis and epiphysis extending to the subchondral bone. Both patients were found to have pathology-confirmed giant cell tumors requiring curettage and cementation. Although commonly involving the epiphysis and subchondral bone, giant cell tumors of long bone can present as isolated metaphyseal lesions. Careful examination of radiographs and early detection may make these lesions easier to treat, reducing the risk of recurrence and damage to the articular surface. © The Japan Society of Clinical Oncology 2021.