Rheumatoid pulmonary nodules: clinical and imaging features compared with malignancy

Area of Science:

• Pulmonology
• Radiology
• Rheumatology

Background:

• Rheumatoid lung nodules are a common manifestation of rheumatoid arthritis, but differentiating them from lung malignancy can be challenging.
• Accurate differentiation is crucial for appropriate patient management and avoiding unnecessary invasive procedures.

Purpose of the Study:

• To identify distinct clinical and imaging characteristics that differentiate rheumatoid lung nodules from lung malignancies.
• To improve diagnostic accuracy for rheumatoid lung nodules using computed tomography (CT) and positron emission tomography/computed tomography (PET/CT).

Main Methods:

• Retrospective review of 73 patients with histologically confirmed rheumatoid and malignant lung nodules.
• Analysis of medical records and blinded review of CT and PET/CT imaging studies.
• Comparison of clinical and imaging features between patients with rheumatoid lung nodules and lung malignancy.

Main Results:

• Patients with rheumatoid lung nodules were younger, more likely to have subcutaneous nodules, and rheumatoid factor seropositivity compared to those with malignancy.
• CT findings suggestive of rheumatoid nodules included multiplicity, smooth borders, cavitation, satellite nodules, pleural contact, and a subpleural rind.
• PET/CT showed lower metabolism (SUVmax) and lack of fluorodeoxyglucose (FDG)-avid draining lymph nodes in rheumatoid nodules.

Conclusions:

• Rheumatoid lung nodules exhibit distinct clinical and imaging features that differentiate them from lung malignancies.
• A combination of CT findings (e.g., multiplicity, cavitation, smooth borders) and PET/CT characteristics (low metabolism) can aid in diagnosis.
• These findings can help clinicians distinguish rheumatoid nodules from cancer, potentially reducing the need for biopsies.