Diffuse panbronchiolitis: Histologic diagnosis in unsuspected cases involving North American residents of Asian descent

Objective. - To study and report two cases of diffuse panbronchiolitis in patients of Asian ancestry residing in the United States and to review the literature pertaining to this disease. Design. - Diffuse panbronchiolitis is a progressive interstitial pneumonitis occurring primarily in Japan. Rare cases are now being identified in Europe and North America. Patients often have a history of sinusitis, present with dyspnea on exertion, and show a restrictive pattern on pulmonary function tests. The clinical, radiologic, and pathologic features of two cases of the disease received for consultation at the Armed Forces Institute of Pathology, Washington, DC, are reported with a review of the literature. Results. - Chest radiographs revealed bilateral small nodular opacities with ill-defined borders. High-resolution computed tomography demonstrated the abnormalities to have a centrilobular distribution. Histologically, there was transmural chronic inflammation centered on the terminal bronchioles and an interstitial infiltrate of foamy macrophages. Conclusion. - Diffuse panbronchiolitis may be mistaken for other more common small airway diseases and may be underrecognized in Western nations. The immigration of Asians and sporadic case reports involving non- Asians make recognition of this disease entity important, as the implications for therapy are different than that of other small airway diseases.