A Case of Endobronchial Actinomycosis

Actinomycosis is an infectious disease caused by certain Actinomyces species. Actinomyces are Gram-positive, non-spore forming organisms characterized by obligate or facultative anaerobic rods that normally inhabit anaerobic niches of the human oral cavity. Cervicofacial, abdominal, pelvic and thoracic infections of Actinomyces are not uncommon, but endobronchial actinomycosis is rarely reported. Endobronchial actinomycosis can be misdiagnosed as unresolving pneumonia, endobronchial lipoma or malignancies. Endobronchial actinomycosis should be included in the differential diagnosis of any endobronchial mass. We report a case of a 43-year-old man who presented with a productive cough and pulmonary consolidation at the right lower lobe on chest radiograph. Fiberoptic bronchoscopy revealed obstruction of the right superior segment of the lower bronchus with an exophytic endobronchial mass. Endobronchial actinomycosis was confirmed by demonstration of sulfur granules in the bronchoscopic biopsy of the mass. Intravenous administration of penicillin G followed by oral amoxacillin/clavulanic acid therapy for 3 months resulted in improving symptoms. Infiltrative consolidation on the chest X-ray was markedly decreased.