A 68-year-old man with long-standing tophaceous gout presents with acute onset of severe pain, swelling, and inability to bear weight on the right ankle. X-ray shows well-defined erosions with overhanging edges and preserved joint space. The characteristic radiographic finding of chronic tophaceous gout described as 'punched-out' erosions with overhanging edges is also known as:
- A Bamboo spine
- B Rat bite erosions ✓
- C Mouse erosions
- D Hole-within-a-hole appearance
Correct answer: B. Rat bite erosions
Explanation
Rat bite erosions describe the well-defined, punched-out erosions with overhanging margins (rat bite appearance) seen in chronic tophaceous gout. These occur in periarticular and subchondral bone with relative preservation of joint space early in disease. Bamboo spine is seen in ankylosing spondylitis. Mouse erosions and hole-within-a-hole are not recognized radiographic descriptions.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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