This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bones, Subject name: Pathology
[{'content': 'Giant cell is seen in: (PGI Dec 2006) \nSelect and explain. \nA. Osteoclastoma, B. Chondroblastoma, C. Chordoma, D. Osteitis fibrosa cystisca', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans: A (Osteoclastoma) (Ref: Maheshwarl 3rd/216]Osteoclastoma (Giant Cell Tumour)Pathology: 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", 'role': 'assistant'}]