A 55-year-old male presents with a painful enlarging submandibular swelling that increases at mealtimes. Ultrasound shows a hyperechoic shadow with posterior acoustic shadowing in the submandibular duct. The most common composition of submandibular salivary calculi is:

• A Calcium oxalate
• B Uric acid
• C Cholesterol monohydrate
• D Calcium phosphate (hydroxyapatite) and carbonate ✓

Explanation

Salivary gland calculi (sialolithiasis) are composed primarily of calcium phosphate (predominantly hydroxyapatite) with calcium carbonate, magnesium phosphate, and organic matrix components. The submandibular gland accounts for 80% of salivary calculi due to its high mucin content, alkaline saliva, and the anti-gravity course of Wharton's duct. Most submandibular stones are radio-opaque on plain X-ray; parotid stones are often radiolucent. Calcium oxalate is a urinary stone; uric acid stones occur in gout; cholesterol forms gallstones.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.