<prompt> Variant of Giant cell tumor isOssifying fibromaNon Ossifying fivromaOsteosarcomaChondtoblastoma  <response>: GCT is adult counterpa of chondroblastoma. Chondroblastoma is an epiphyseal tumor which occurs in 2nd decade while GCT is an epiphyseal tumor which occurs in adults Refer https :emedicine. Medscape.comaicle125449-overview 