A43-02 Rethinking Disease Progression in Fibrotic Hp: Ppfe-like Changes as a Red Flag

Abstract Introduction In non-idiopathic pulmonary fibrosis (IPF) interstitial lung disease (ILD), criteria for fibrotic progressive disease are controversial given that some require a 12-month observation to fulfill the diagnosis and start of antifibrotic therapy. However, pleuroparenchymal fibroelastosis (PPFE) is a rare ILD characterized by fibroelastotic thickening of the visceral pleura and subpleural lung parenchyma, predominantly in the upper lobes. It may occur idiopathically or secondary to other conditions and has been increasingly associated with fibrotic hypersensitivity pneumonitis (f-HP). We report two cases of f-HP with PPFE features discussed in a multidisciplinary team (MDT), where early treatment was initiated without waiting for formal progression criteria. Case 1 An 80-year-old woman presented with dyspnea (mMRC 2/4) and long-term exposure to domestic poultry. Chest CT (Figure 1. upper left) showed mosaic attenuation, ground-glass opacities, and upper-lobe fibrosis with apical pleural thickening and tracheal deviation. A minimum intensity projection (MinIP) revealed severe upper-lobe predominant air trapping suggestive of f-HP with PPFE-like changes (Figure 1 bottom left). Biopsy was not feasible. Pulmonary function tests: TLC 3.10 L (83%), FVC 1.13 L (61%), RV 1.97 L (118%), RV/TLC 63%, DLCO 32%. Her six-minute walk distance was 318m (61%) with exertional desaturation. Management included oxygen, pulmonary rehabilitation, nutritional and palliative support. Systemic corticosteroids were initiated. Antifibrotic therapy was deferred due to frailty and low BMI (15 kg/m²), to be reconsidered if her clinical status improved. Case 2 A 76-year-old woman presented with 18 months of fatigue, dyspnea (mMRC 2/4), dry cough, and 18 kg weight loss. She reported exposure to two pet ducks. Examination revealed suprasternal retraction and fine crackles on the right upper chest. Chest CT (Figure 1 upper right) demonstrated irregular tracheal course, extensive ground-glass opacities with nodular and irregular septal thickening, and expiratory air trapping with a “three-density pattern,” along with right apical pleural thickening and pleural bands consistent with PPFE features. Biopsy was not feasible. The ILD-MDT concluded f-HP with concomitant PPFE-like lesions indicating poor prognosis. Antifibrotic therapy, systemic steroids, pulmonary rehabilitation, and exposure avoidance were started immediately. Discussion PPFE is a severe ILD with predominant upper-lobe involvement. Diagnosis is radiological with or without histopathology, with Watanabe et al. offering the latest criteria. Prognosis is poor, and although no curative therapy exists, antifibrotics benefits progressive fibrosing phenotypes. Coexistence of PPFE in f-HP suggests a more aggressive disease behavior, prompting early recognition and timely initiation of antifibrotics, exposure removal, and rehabilitation. This abstract is funded by: None