This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Which of the following condition is associated with a classical expansive lytic lesion in the transverse process of a veebra on an X ray? \nSelect and explain. \nA. Metastasis, B. Osteosarcoma, C. Osteoblastoma, D. Aneurysmal bone cyst', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Aneurysmal bone cysts are benign highly vascular bony lesions. It occur in the second decade of life and has a tendency to involve the posterior elements of the veebrae. Most commonly it is located in the cervical and thoracic spine. X ray shows an expansile, lytic lesion with bubbly appearance surrounded by a thin shell of reactive bone. Fine bony septations give the lesion a soap bubble appearance. Ref: The Growing Spine: Management of Spinal Disorders in Young Children By Behrooz A. Akbarnia, Page 126; Essential Ohopedics, 3rd Edition By J Maheswari, Page 215, 218-9.', 'role': 'assistant'}]