A 55-year-old man with recurrent attacks of acute first metatarsophalangeal joint pain has a foot radiograph showing an eccentric erosion at the medial aspect of the first MTP head with a sclerotic margin and an 'overhanging edge', with preservation of the joint space. The most likely diagnosis is:

• A Chronic tophaceous gout ✓
• B Rheumatoid arthritis
• C Osteoarthritis of the first MTP joint
• D Psoriatic arthritis

Explanation

Eccentric juxta-articular erosions with sclerotic margins and overhanging edges, with relative preservation of joint space until late disease, are classic for chronic tophaceous gout. Rheumatoid arthritis produces marginal erosions at the bare areas with uniform joint space narrowing and periarticular osteopenia, which distinguishes it from the eccentric, well-corticated gouty erosion.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.