Clinical Features Distinguishing Tumors From Tumor-Like Lesions in Patients With Rheumatoid Arthritis: An...

Area of Science:

• Musculoskeletal oncology
• Rheumatology
• Diagnostic imaging

Background:

• Rheumatoid arthritis (RA) can cause lesions like synovitis and rheumatoid nodules.
• These RA-related lesions can be mistaken for bone or soft tissue tumors, leading to diagnostic challenges.

Purpose of the Study:

• To identify clinical features differentiating true tumors from tumor-like lesions in RA patients.
• To improve diagnostic accuracy for musculoskeletal masses in RA patients.

Main Methods:

• Retrospective review of 70 RA patients with suspected musculoskeletal tumors.
• Categorization into newly diagnosed RA with tumor-like lesions, established RA with tumor-like lesions, and established RA with true tumors.
• Analysis of clinical characteristics, MRI findings, and histologic results, using logistic regression.

Main Results:

• True tumors were associated with older age (median 69 vs 55 years) and extra-articular locations (96% vs 28%).
• Specific MRI patterns (low-to-intermediate T1, heterogeneous high T2 signals) were more common in tumor-like lesions (83%) than true tumors (43%).
• Older age and extra-articular location were significant predictors of true tumor diagnosis.

Conclusions:

• Older age and extra-articular location are indicators for true tumors in RA patients, though confidence intervals are wide.
• MRI findings alone are insufficient for definitive differentiation.
• Histologic confirmation is essential for accurate and timely diagnosis of musculoskeletal masses in RA patients.