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
All of the following are true about this condition except: 
Select and explain. 
A. 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
D: Diagnosed by MRI
Answer: D: Diagnosed by MRI 
Explanation: 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.