This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal System, Subject name: Radiology
Cleavage plane sign is seen in? 
Select and explain. 
A. Parosteal osteosarcoma, B. Ewing's sarcoma, C. Chondrosarcoma, D. Metastasis
A: Parosteal osteosarcoma
Answer: A: Parosteal osteosarcoma 
Explanation: Ans AParaosteal sarcoma arises exophytically from long bones and thus there is a small plane of cleavage between it and the main shaft of bone - the Cleavage plane sign.