Clinical and prognostic significance of intrathoracic lymphadenopathy in fibrosing interstitial lung diseases

Abstract

Background. Mediastinal lymph node (MLN) enlargement is a common radiological finding in fibrosing interstitial lung diseases (fILDs). However, its clinical and prognostic significance across different disease entities remains poorly characterized. Aim. To assess the prevalence of intrathoracic lymphadenopathy in idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis (fHP), and systemic sclerosis-associated fibrosing interstitial lung disease (fILD-SSc), and to determine its associations with disease characteristics, progression, and prognosis. Materials and methods. This retrospective two-center cohort study included 533 patients: 151 with IPF, 279 with fHP, and 103 with fILD-SSc. MLN enlargement was defined as a lymph node short-axis diameter ≥ 10 mm. The number of enlarged MLNs was also assessed semiquantitatively. Logistic regression, Kaplan–Meier analysis, and Cox regression were used to evaluate prognostic significance. Results. Intrathoracic lymphadenopathy was detected in 39.4% of patients with IPF, 57.0% with fHP, and 36.2% with fILD-SSc (p = 0.001). In the overall cohort, enlarged MLNs were associated with a usual interstitial pneumonia pattern (odds ratio – OR 1.69, 95% confidence interval – CI 1.18–2.44; p = 0.004) and mortality (OR 3.39, 95% CI 2.11–5.45; p 0.0001). The association with mortality was confirmed by Kaplan–Meier analysis (p = 0.028) and Cox regression (hazard ratio 1.50, 95% CI 1.03–2.17; p = 0.033). In IPF, MLN enlargement was associated with mortality (OR 5.83; p = 0.001), whereas in fHP it was associated with both disease progression (OR 2.53; p = 0.001) and mortality (OR 3.59; p 0.0001). In fILD-SSc, intrathoracic lymphadenopathy was associated with a greater extent of lung involvement as assessed by the Goh score (β = 0.219; p = 0.026), but not with disease progression or prognosis. Conclusion. MLN enlargement is a radiological feature associated with an unfavorable course of fILD, with the strongest prognostic significance observed in IPF and fHP. Semiquantitative assessment of the number of enlarged MLNs did not demonstrate prognostic significance.