<prompt> A variant of Giant cell tumor is?Ossifying fibromaNon ossifying fibromaOsteosarcomaChondroblastoma  <response>: GCT is adult counterpart of chondroblastoma. Chondroblastoma is an epiphysis tumor which occurs in the 2nd decade 10-20 years, while GCT is an epiphysis tumor which occurs in adults 20 - 40 years. 