Abstract Introduction Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a necrotizing small-vessel vasculitis characterized by eosinophilic inflammation and granulomatous involvement of the respiratory tract. Pulmonary manifestations typically include transient or migratory infiltrates, nodules, or diffuse alveolar hemorrhage (DAH). Unilateral consolidation is exceedingly rare and may mimic infection or malignancy, especially in patients lacking asthma or peripheral eosinophilia. Here, we present a case of MPO-ANCA-positive EGPA manifesting as unilateral pulmonary consolidation and alveolar hemorrhage in a patient with underlying emphysema. Case Presentation A 46-year-old man with a history of heavy tobacco use and vaping presented with six months of progressive dyspnea and cough, followed by two days of hemoptysis. He denied illicit drug use or occupational exposures. On admission, he developed acute hypoxemic respiratory failure requiring mechanical ventilation. Chest X-Ray showed a dense left lung consolidation (Figure 1) and chest CTA demonstrated advanced paraseptal and centrilobular emphysema with cystic airspace disease and predominant left upper lobe consolidation with patchy ground-glass opacities (Figure 2). Infectious workup was negative. Bronchoalveolar lavage was hemorrhagic, revealing numerous nucleated cells. Transbronchial biopsy of the left lung showed poorly formed granulomas with eosinophilic infiltration, fibrin deposition, and vasculitic changes (Figure 3,4). Laboratory testing revealed elevated ESR and CRP, with increased p-ANCA titers and elevated anti-myeloperoxidase (MPO); anti-GBM, PR3, and CCP antibodies were negative. The patient received intravenous methylprednisolone, rituximab, and plasma exchange. Renal function remained normal, and respiratory status improved with continued immunosuppression. Discussion MPO-ANCA-associated EGPA can present with limited pulmonary disease and atypical imaging features. Unilateral DAH or consolidation is an exceptionally uncommon manifestation, rarely reported in the literature and poses a significant diagnostic challenge. The absence of renal, neurologic, or upper airway involvement can delay recognition. Histopathologic confirmation remains key. Although the diagnostic yield of transbronchial biopsy (TBB) in vasculitis is limited, targeted sampling of radiographically active lesions may demonstrate the characteristic combination of eosinophilic vasculitis and granulomatous inflammation. Early identification and timely initiation of immunosuppressive therapy are critical to prevent irreversible pulmonary damage. Conclusion This case illustrates a rare presentation of MPO-ANCA-positive EGPA manifesting as unilateral consolidation and alveolar hemorrhage in a patient with underlying emphysema. EGPA should be considered in patients with unexplained unilateral infiltrates after exclusion of infection and malignancy. Targeted TBB may provide a minimally invasive diagnostic pathway in pulmonary-limited vasculitis. This abstract is funded by: None
Lemus et al. (Fri,) studied this question.