Hypereosinophilic obliterative bronchiolitis clinically mimicking diffuse panbronchiolitis: four-year follow-up

A 73-year-old man with a known history of asthma presented with dyspnea, worsening wheezing and a productive cough complicated by chronic sinusitis. Chest computed tomography showed bronchial wall thickening with centrilobular nodules and ground-glass opacity in the right lower lobe. Features meeting the diagnostic criteria for diffuse panbronchiolitis (DPB) were identified, and lobectomy confirmed the presence of lung cancer. Over the subsequent four years, the patient's symptoms worsened. We reevaluated a lung lobe specimen, which showed hypereosinophilic obliterative bronchiolitis (HOB). A transbronchial lung biopsy also indicated bronchitis with eosinophilic infiltration. Our initial diagnosis of DPB was subsequently changed to HOB after four years. We herein describe this case of HOB, which was initially diagnosed as DPB primarily based on high-resolution computed tomography, with a focus on the histopathology and long-term clinical course. This is the first report to document the long-term clinical course of HOB.