Primary Pulmonary Actinomycosis Mimicking Malignancy

The diagnosis of primary pulmonary actinomycosis (PPA) is still an important challenge in clinical practice due to its clinical and radiographic similarity with other infections and malignant diseases. Currently, the diagnosis can be only made histopathologically. A 67-year-old male patient was admitted to our clinic with the complaints of cough and hemoptysis for the past two months. His physical examination was non-specific. An increased non-homogeneous density was observed in the middle zone of the left hemithorax on chest X-ray. Thoracic computed tomography revealed a hypodense mass. Positron emission tomography revealed a hypermetabolic activity in the malignant mass. The patient was diagnosed with pulmonary actinomycosis through transthoracic fine needle aspiration biopsy. In conclusion, PPA should be considered in the differential diagnosis in patients with malignancy in the presence of predisposing risk factors.