Propionibacterium Acnes-Associated Sarcoidosis Complicated by Acute Bird-Related Hypersensitivity Pneumonitis

BACKGROUND:The number of reports on sarcoidosis complicated by hypersensitivity pneumonitis (HP) is limited, and most describe cases complicated by chronic bird-related HP. Here, we present for the first time a case with Propionibacterium acnes-associated sarcoidosis complicated by acute bird-related HP.CASE PRESENTATION:A 62-year-old man with a past medical history of sarcoidosis was admitted to our department, and chest computed tomography showed diffuse ground-glass opacities, which appeared as he rapidly increased the number of pigeons he kept for a competition. Random transbronchial lung biopsy revealed well-formed non-caseating epithelioid granulomas, which contained positively stained substances on immunohistochemistry using the PAB antibody, a specific monoclonal antibody against P. acnes lipoteichoic acid. Poorly formed non-caseating granulomas without positively stained substances were also detected.CONCLUSION:We describe the successful identification of this exceptionally rare case of sarcoidosis complicated by acute bird-related HP in which two morphologically and immunohistologically different types of granulomas were present in the same lung.