This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal Radiology, Subject name: Radiology
[{'content': 'Osteoporosis circumscripta is seen with? \nSelect and explain. \nA. Fibrous dysplasia, B. Chronic Phenytoin Therapy, C. Cushings syndrome, D. Pagets Disease', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Osteoporosis Circumscripta is focal thinning of bone seen in cases of pagets disease. Fibrous dysplasia shows focal thickening of bone and ground glass appearance. Chronic phenytoin therapy can cause generalized thickening of bone. Cushings syndrome can cause generalized thinning of bone.', 'role': 'assistant'}]