On MRI of the parotid gland, a well-defined oval mass with high T2 signal (bright as CSF), very low T1 signal, and sharp margins is most consistent with:

• A Pleomorphic adenoma
• B Warthin's tumor
• C Simple parotid cyst (first branchial cleft cyst) ✓
• D Mucoepidermoid carcinoma

Explanation

A well-defined parotid lesion with CSF-equivalent signal (very bright T2, very dark T1, no enhancement) represents a simple cyst, most commonly a first branchial cleft cyst in this location. Pleomorphic adenoma is the most common benign parotid tumor and shows heterogeneous high T2 with areas of low signal (myxoid stroma) and moderate enhancement. Warthin's tumor is bilateral in 10%, shows heterogeneous T1/T2 signal with characteristic lipid content, and occurs in older smokers. Mucoepidermoid carcinoma has irregular margins and solid enhancing components.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.