Lung biopsy in rheumatoid arthritis.

Forty open lung biopsies from patients with rheumatoid arthritis and possible "rheumatoid lung disease" were reviewed in an attempt to correlate histology with radiologic, physiologic, and prognostic variables. A wide variety of histopathologic features was seen, and primary and secondary patterns of injury were recognized. Five different groups based on histologic patterns were identified: pulmonary rheumatoid nodules, usual interstitial pneumonia (UIP), bronchiolitis obliterans with patchy organizing pneumonia (BOOP), lymphoid hyperplasia, and cellular interstitial infiltrates. The finding of rheumatoid nodules as the primary pattern imparted a uniformly good prognosis, whereas the pattern of UIP indicated a poor one. Patients with BOOP had a more favorable prognosis than did patients with UIP, as did patients with lymphoid hyperplasia and/or nonspecific cellular interstitial infiltrates. Consistent correlations between pulmonary function testing and roentgenographic and histologic findings were not found. The term "rheumatoid lung disease" is of no use as a histologic diagnosis because it encompasses a broad spectrum of morphologic changes that carry significantly different prognoses.