Chronic Eosinophilic Pneumonia: A Diagnostic Challenge With Atypical Bronchoalveolar Lavage Findings and an Organizing Pneumonia Pattern.

Chronic eosinophilic pneumonia (CEP) is a rare eosinophilic lung disease. We report a 61-year-old man with asthma who presented with progressive exertional dyspnoea for 2 months and worsening productive cough for 2 weeks. Peripheral blood eosinophilia was 15% (1314 cells/μL), and chest computed tomography showed bilateral peripheral, upper-lobe-predominant opacities. Bronchoalveolar lavage (BAL) revealed marked neutrophil predominance (85%) with only 6% eosinophils. Empirical antibiotics produced no clinical or radiographic improvement. Because clinical and radiological suspicion for CEP remained high despite discordant BAL findings, surgical lung biopsy was performed, demonstrating prominent eosinophilic infiltration with an organizing pneumonia pattern, supporting a diagnosis of CEP. The patient responded well to systemic corticosteroids. This case highlights the role of surgical lung biopsy in suspected CEP with atypical BAL findings and illustrates that organizing pneumonia may occur within the histopathological spectrum of CEP.