<prompt> Giant cell is seen in: PGI Dec 2006OsteoclastomaChondroblastomaChordomaOsteitis fibrosa cystisca  <response>: Ans: A Osteoclastoma Ref: Maheshwarl 3rd216Osteoclastoma Giant Cell TumourPathology: The cell of origin is uncertain. Undifferentiated spindle-cells, profusely inter- spersed with multinucleate giant cell. The tumour stroma is highly vascular. These giant cells were mistaken as osteoclasts in the past, hence the name osteoclastoma. The tumour is seen commonly in the age group of 20-40 years.A characteristic egg-shelf crackling is often not elicited. The limb may be deformed if a pathological fracture has occurred.Characteristic radiological feature : Soap-bubble appearance 