Rheumatoid arthritis-associated interstitial lung disease: the relevance of histopathologic and radiographic pattern

Abstract

Interstitial lung disease (ILD) is a frequent extraarticular manifestation of rheumatoid arthritis (RA). While the nonspecific interstitial pneumonia pattern predominates in most forms of connective tissue-associated ILD, studies in patients with RA-associated ILD (RA-ILD) suggest that the usual interstitial pneumonia (UIP) pattern is more common in this patient population. High-resolution CT (HRCT) scans appear accurate in identifying UIP pattern in many patients with RA-ILD. Although the data are limited, UIP pattern appears to predict worse survival in RA-ILD patients. Larger, prospective, multicenter studies are needed to confirm this finding. We propose that the evaluation of patients with RA-ILD should focus on identifying those with UIP pattern on HRCT scans, as these patients are likely to carry a worse prognosis. In patients in whom the underlying pattern cannot be determined by HRCT scanning, surgical lung biopsy should be considered.

Figures

Figure 1

Radiographic and histopathologic appearances of NSIP and UIP. A: NSIP pattern; HRCT scan demonstrating the characteristic radiographic appearance of NSIP with bilateral, ground-glass opacities. B: NSIP pattern; lung biopsy specimen demonstrating a homogeneous cellular infiltrate typical of NSIP pattern. C: UIP pattern; HRCT scan demonstrating the characteristic radiographic appearance of a UIP pattern with bibasilar, reticular abnormalities, traction bronchiectasis, and honeycombing. D: UIP pattern; a lung biopsy specimen demonstrating areas of established fibrosis next to normal lung and focal fibroblastic activity (fibroblast foci) typical of UIP pattern (arrows). Although honeycombing is not seen on this view, the image demonstrates the classic “temporal heterogeneity” of UIP pattern.

Figure 2

Proportions of histopathologic UIP and NSIP in patients with CTD-ILD. Combined data from published case series of patients with various forms of CTD-ILD demonstrate that UIP pattern is more common in patients with RA-ILD. The following are data compiled and aggregated from multiple studies: scleroderma,,; myositis,–; Sjögren syndrome,,; undifferentiated CTD; and RA.,,,,

Figure 3

Survival data from a cohort of 28 patients with RA-ILD were compared with data from other patients with CTD-ILD and IPF. Patients with RA-ILD and UIP pattern (RA-UIP) had a worse survival time than patients with CTD-ILD and NSIP pattern (CVD-NSIP; p = 0.04), and were no different from patients with IPF. CVD = collagen vascular disease. Redrawn from Park et al with permission.

Figure 4

Proposed algorithm for the evaluation and management of suspected patients with RA-ILD. Patients with suspected RA-ILD should be screened annually for the presence of ILD with a history and a physical examination. In suspected cases of ILD, additional testing with PFTs and HRCT scanning is indicated. In the absence of a definitive radiographic pattern, surgical lung biopsy should be considered.