Organizing pneumonia preceding rheumatoid arthritis.

Rheumatoid arthritis patients are susceptible to interstitial lung disease, and joint manifestations of rheumatoid arthritis usually precede lung involvements by several years. Organizing pneumonia, as the first manifestation of rheumatoid arthritis, is extremely rare, and its clinical features remain currently unknown. We present a case and a literature review of patients who were pathologically diagnosed with organizing pneumonia first and met the diagnostic criteria of rheumatoid arthritis later. In this review, we observed the following: (1) patients with organizing pneumonia preceding rheumatoid arthritis have a high prevalence of rheumatoid factor or anticyclic citrullinated peptide antibodies; (2) almost all patients developed rheumatoid arthritis within one year after the diagnosis of organizing pneumonia. We suggest that patients with organizing pneumonia and positive for either rheumatoid factor or anticyclic citrullinated peptide antibody should be cautiously followed up regarding the development of rheumatoid arthritis, particularly during the first year after the diagnosis of organizing pneumonia.