Abstract
Pulmonary actinomycosis is a rare chronic purulent granulomatous disease, which can be easily misdiagnosed as lung cancer, tuberculosis, and other diseases. However, diagnosis relies on histopathological evidence, and early diagnosis is conducive to the patient's recovery. In this study, a case of a 70-year-old man with a soft tissue density mass at the right lower lung was studied, with initial chest CT suggesting lung cancer, pulmonary actinomycosis was confirmed by subsequent pathological biopsy of lung tissues eventually. The patient responded well to antibiotics treatment. This paper is to explore the clinical characteristics of the disease, providing insight into the disease, and its diagnosis and treatment.