American Board of Internal Medicine (ABIM) Certification Practice Exam

Which condition is primarily characterized by the presence of central erosions on imaging?

1. Rheumatoid arthritis

2. Osteoarthritis

3. Gout

4. Sclerosis

The correct answer is: Osteoarthritis

The condition primarily characterized by the presence of central erosions on imaging is rheumatoid arthritis. In rheumatoid arthritis, these erosions occur due to the inflammatory process that targets the synovial lining of the joints, leading to the destruction of bone and cartilage. As a result, imaging studies such as X-rays or MRIs often reveal central erosions, particularly in the hands and feet where the disease is most commonly assessed. In contrast, osteoarthritis, although it may show changes in joint structure, typically presents with joint space narrowing, osteophytes, and subchondral sclerosis, rather than central erosions. Gout can lead to erosions as well but is often characterized by the presence of tophi and can display a different pattern of bone erosion. Sclerosis refers to hardening or thickening of tissues and does not primarily manifest with central erosions on imaging. Thus, the emphasis on rheumatoid arthritis as the correct answer is rooted in its distinct pathological process which leads to the diagnosis of central erosions on imaging.