Tracheobronchial lesions in eosinophilic pneumonia

Abstract

Eosinophilic pneumonia (EP) is characterized by eosinophil infiltration in the lung parenchyma. However, tracheobronchial lesions associated with the disease have been poorly described. To clarify the frequency and characteristics of cases with tracheobronchial lesions in EP, we performed a retrospective review of EP patients. We included 36 EP cases seen from January 2004 to December 2007 at the Kinki-Chuo Chest Medical Center. The incidence of tracheobronchial nodules and associated clinical features were analyzed. Of these 36 patients, 29 had chronic eosinophilic pneumonia (CEP); 1, acute EP; 3, drug-induced EP; 2, allergic bronchopulmonary aspergillosis; and 1, parasite-related EP. Only 2 of the 29 CEP cases had tracheobronchial lesions. For both of these cases, bronchoscopy revealed multiple whitish nodules on the tracheobronchial mucosa. The associated histopathological findings revealed squamous metaplasia and eosinophil infiltration in the subepithelial region. In both cases, the nodules disappeared after steroid therapy. The prevalence of tracheobronchial lesions was 6.9% in CEP patients and 5.6% in EP patients overall. EP patients were divided into 3 groups: CEP with nodules (n=2), CEP without nodules (n=27), and other EP (n=7). We found that the CEP with nodules group showed a relatively higher incidence of respiratory symptoms, higher white blood cell (WBC) count, and higher levels of peripheral and bronchoalveolar eosinophilia than the other groups. Tracheobronchial nodules represent rare observations within the EP population, which are likely to reflect a severe disease condition.