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: ENT
[{'content': 'Mucocele is commonly seen is sinus - \nSelect and explain. \nA. Frontal, B. Maxillary, C. Ethmoid, D. Sphenoid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A mucocele is an epithelial lined, mucus containing sac completely filling the sinus and capable of expansion:\n\nMucocele are most commonly formed in Frontal sinus followed by ethmoid, sphenoid and maxillary sinuses.\nMucocele of frontal sinus presents as a swelling in the floor of frontal sinus above the inner (medial) canthus. It displaces the eyeball forward, downward and laterally.\n\nIOC = CT scan\nTOC = Endoscopic sinus surgery\nAccording to Dhingra,\n\nLeast common sinus assopciated with Mucocele formation is sphenoid.\nBut Scott Brown says:\n\n–– Most of the cases of mucocele of sphenoid sinus are referred to neurosurgeons. Therefore, it seems it is less common but actually the sinus least involved by mucocele is maxilla.', 'role': 'assistant'}]