Fig. 1

Temporal progression of pulmonary features on lung High-Resolution Computed Tomography (HRCT), axial view. A) Lung HRCT scan performed at disease onset showing small peri-bronchial consolidations in the apical segment and subpleural region of the posterior basal segment of the right lower lobe, with additional small peripheral consolidations in the posterior segment of the right upper lobe. (B) Lung HRCT performed four months after oral cyclophosphamide initiation and before tofacitinib therapy, showing persistent thickening of the intralobular and interlobular interstitium with reduced density and less consolidation compared to the previous scan (apical and posterior segments of the upper lobe, all segments of the lower lobe, and the lateral segment of the middle lobe) in the right lung; peri-bronchial interstitial thickening in the peri-hilar region; a small hyperdense area is observed in the anterior segment of the left upper lobe (subpleural). (C) Lung HRCT performed six months after tofacitinib initation, demonstrating nearly complete resolution of the pathological findings, showing a residual area of mild subpleural ground-glass opacity on the right lobe. (D) Lung HRCT performed two years after tofacitinib initiation, revealing minimal ground-glass opacity in the subpleural region of the right upper lobe, mild septal, pleural and interlobular septal thickening at the apices