This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of orbit, Lids and lacrimal apparatus, Subject name: Ophthalmology
[{'content': 'A patient presented with unilateral proptosis which was compressible and increases on bending forward. No thrill or bruit was present. MRI shows a retroorbital mass with enhancement. The likely diagnosis is- \nSelect and explain. \nA. AV malformations, B. Orbital encephalocoecle, C. Orbital varix, D. Neurofibromatosis', 'role': 'user'}, {'content': "Answer: C \nExplanation: *Proptosis on bending forward is typical of intermittent proptosis. Orbital varices constitute about 90% of cases of intermittent proptosis). So, it is seen in venous malformation, i.e orbital varixes. *AV malformation and encephalocele cause pulsatile exophthalmos. Ref: Henderson's orbital tumors 2nd/e p.404", 'role': 'assistant'}]