Fig. 3

Random transbronchial lung biopsy. a Random transbronchial lung biopsy specimens show well-formed non-caseating epithelioid granulomas with clear margin, characteristic of sarcoidosis, in the right B4a bronchus. Immunohistochemistry using PAB antibody [10] showing positively stained substances in these granulomas. b Poorly formed non-caseating granulomas characteristic of HP without positively stained substances in both the right B8a and B3a bronchus simultaneously