Unenhanced CT of a 22-year-old man being evaluated after trauma incidentally shows a well-defined exophytic cortical lesion in the right kidney measuring 25 HU, containing macroscopic fat attenuation with no calcification. Which underlying syndrome should be specifically considered?

• A Tuberous sclerosis ✓
• B von Hippel-Lindau disease
• C Autosomal dominant polycystic kidney disease
• D Medullary carcinoma of the kidney

Explanation

B renal angiomyolipoma is diagnosed on CT by macroscopic fat attenuation within a cortical mass, and about 80 percent of patients with tuberous sclerosis develop these tumours, often multiple and bilateral. Von Hippel-Lindau disease predisposes to renal cell carcinomas and cysts, which typically enhance and lack fat. Detection of fat essentially excludes renal cell carcinoma, though rare fat-containing RCC exists, making clinical correlation important.

Reference: Radiology Review Manual, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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