This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Salivary Glands, Subject name: Surgery
[{'content': 'All of the following are true about this condition except: \nSelect and explain. \nA. Mucous extravasation cyst arising from sublingual gland, B. Treated by marsupialization, C. Most common structure injured during ranula surgery is submandibular duct, D. Diagnosed by MRI', 'role': 'user'}, {'content': 'Answer: D \nExplanation: RANULA - A cystic swelling in the floor of mouth that resembles a frog belly - Term ranula should only be applied to a mucous extravastion cyst that arises from the sublingual gland. ETIOLOGY - Commonly the lesions is induced by local trauma and duct rupture, followed by mucin spillage into th surrounding soft tissues ( Mucosa extravasation phenomenon) - Uncommonly, it is due to obstruction probably caused by mucous plug or a sialolith HISTOPATHOGOLY - Mucin accumulation surrounded by granulation and Fibrous tissue (mucous extravasation phenomenon) - A cyst filled mucin and lining by the ductal epithelium (mucous retention cyst) Clinical features - Exclusively present on the floor of mouth - Usually unilateral, lateral to midline - Smooth, dome shape, fluctuating and painless swelling - The color is usually bluish, but keep lesion may have a normal color - The size varies from a few to several centimeters in diameter. Very large lesion which may occupy the floor of mouth can also occur. Diagnosis - Diagnosis is usually made clinically Treatment - Surgical removal or marsupialization - MC structure injured during ranula surgery: Submandibular duct.', 'role': 'assistant'}]