Surgical Pathology of Diffuse Parenchymal Lung Disease in Patients With Psoriasis or Psoriatic Arthritis

Diffuse parenchymal lung disease (DPLD) is a well-recognized complication of systemic connective tissue disease (CTD) but rarely arises in patients with psoriasis or psoriatic arthritis, a poorly understood phenomenon. Objective.-To characterize DPLD associated with psoriasis or psoriatic arthritis, with or without prior immunomodulation. Design.-Pathology consultation files were searched for patients having psoriasis or psoriatic arthritis and DPLD. After excluding cases with active infection or smoking -related DPLD only, 44 patients (22 women; median age, 60 years; range, 23-81 years) were enrolled. Clinical history and pathology slides were reviewed. Results.-Twenty-seven of 44 patients (61%) had psoriatic arthritis; the remainder had psoriasis alone. Most presented many years later with nonspecific respiratory symptoms. Nearly one-third had no prior immunosuppres-sion, and most had no concomitant CTD. Radiographically, ground-glass opacities, consolidation, and/or reticulation were typical. Histologically, nonspecific interstitial pneu-monia and unclassifiable fibrosis were seen in 24 patients (55%) and 8 patients (18%), respectively; usual interstitial pneumonia and airway-centered fibrosis were rare. Super-imposed acute lung injury was common, usually manifest-ing as organizing pneumonia. Lymphoplasmacytic infiltrates, lymphoid aggregates, and chronic pleuritis were frequent. Interstitial granulomas were seen in 17 patients (39%) but were usually rare, poorly formed, and non-necrotizing. No histologic differences were apparent among patients with or without concomitant CTDs or prior therapy. Conclusions.-Some patients with psoriasis or psoriatic arthritis develop clinically significant DPLD, even without prior therapy. Histopathologic findings mirror changes seen with other CTDs. Additional studies are warranted to clarify the association between psoriasis or psoriatic arthritis and DPLD. (Arch Pathol Lab Med. 2023;147:525-533; doi: 10.5858/ arpa.2021-0616-OA)

Automated summary

It has been observed that some patients with psoriasis or psoriatic arthritis develop diffuse parenchymal lung disease (DPLD), even without prior immunomodulation therapy. This phenomenon is not well understood and requires further research to clarify the association between psoriasis or psoriatic arthritis and DPLD.