An overview of thoracic actinomycosis: CT features

BACKGROUND Thoracic actinomycosis is an uncommon, chronic suppurative bacterial infection caused by actinomyces species, especially Actinomyces israelii. METHODS It is usually seen in immunocompetent patients with respiratory disorders, poor oral hygiene, alcoholism and chronic debilitating diseases. RESULTS We illustrate the radiological manifestations of thoracic actinomycoses in various involved areas in the thorax. CONCLUSION Thoracic actinomycosis can be radiologically divided into the parenchymal type, the airway type including bronchiectasis, the endobronchial form, and the mediastinum or chest wall involvement type. TEACHING POINTS • Important risk factors for thoracic actinomycosis are underlying respiratory disorders such as emphysema and chronic bronchitis. • Different CT patterns can be distinguished in thoracic actinomycosis: parenchymal, bronchiectatic, endobronchial and extrapulmonary. • Typical CT findings in the parenchymal pattern are a central low density within the parenchymal consolidation and adjacent pleural thickening.