Temporal changes in mediastinal lymphadenopathy in patients with idiopathic pulmonary fibrosis

Background: Mediastinal lymph node enlargement (LNE) is commonly identified in patients with idiopathic pulmonary fibrosis (IPF), however its clinical significance and temporal progression is poorly understood. Aim: To investigate the incidence of mediastinal LNE in IPF, its progression over time, and relationship to patient demographics and outcomes in a single centre UK cohort. Methods: Patients with a multi-disciplinary diagnosis of IPF and 2 sequential chest computed tomographs (CTs) were retrospectively identified from the Southampton Interstitial Lung Disease Database. Patients with an alternative cause for LNE were excluded. Two radiologists independently reviewed CTs for mediastinal LNE (short-axis diameter ≥10mm). Findings were related to patient demographics and outcomes. Results: 37 patients were identified. 29 (78%) were male, mean age at baseline CT was 73 years and 21 (57%) were ex-smokers. Median time between CTs was 16 months (7-74), and median follow-up time was 42 months (9-94). At baseline CT, 23 patients (62%) had mediastinal LNE, most commonly in station 4. Patients with LNE were typically male (87% vs. 64%), with reduced FVC (74% vs. 86%) and DLCO (45% vs. 59%). Mean size of the largest node was 14mm (10-17mm), with progression on interval CT in 20 patients (87%) to a mean size of 15mm (11-20mm). 4 patients (29%) with no LNE at baseline developed LNE on interval CT. At 3 years follow up, 5 (22%) in the LNE group were deceased and 0 (0%) in the no LNE group. LNE progression was not associated with increased mortality. Conclusions: In this cohort intrathoracic LNE was common, more prevalent in patients with greater physiological impairment, and progressed over time.