Limited Role of Auxiliary Endobronchial Biopsy in the Diagnosis of Japanese Patients with Sarcoidosis

Abstract

The diagnosis of sarcoidosis, a multisystem granulomatous disease of unknown etiology, is established when clinicoradiological findings are supported by histological evidence of non-caseating epithelioid cell granulomas. For pathological diagnosis, an endobronchial biopsy of normal-appearing bronchial mucosa in combination with transbronchial lung biopsy (TBLB) has been reported to be useful for sarcoidosis patients in Europe or the U.S. This is the first report assessing the utility of endobronchial biopsy for diagnosis of Japanese patients with sarcoidosis. Eighteen consecutive patients with strongly suspected sarcoidosis were evaluated by endobronchial biopsy of normal-appearing bronchial mucosa, together with TBLB and bronchoalveolar lavage. The TBLB specimens demonstrated non-caseating epithelioid cell granulomas in the lungs of 11 patients (61.1%), but not any specific findings in those of other 7 patients. In contrast, endobronchial biopsy specimens confirmed a diagnosis of sarcoidosis in only one patient that required steroid therapy for deterioration of pulmonary sarcoidosis. All 18 patients of this study, including 5 patients with pathological findings obtained from extrapulmonary sites, met the pathological or clinical diagnostic criteria. In conclusion, endobronchial biopsy of normal-appearing bronchial mucosa in combination with TBLB does not improve the diagnostic capacity for detecting sarcoidosis in Japanese patients, despite earlier reports. Thus, this method is of limited usefulness as a conventional diagnostic modality for Japanese patients with suspicious sarcoidosis. The present study also suggests the racial difference in the endobronchial involvement in pulmonary sarcoidosis.