[Thoracic actinomycosis: clinical, radiological, and pathological findings in 11 cases]

Most cases of thoracic actinomycosis (TA) have been surgically diagnosed and treated, since it is difficult to distinguish this condition from lung cancer. To clarify the features that are useful for the radiological diagnosis of TA, we analyzed the correlation between the radiological and pathological findings. TA was histologically diagnosed in the 11 patients of the present study, who were admitted to our hospital between 1976 and 2001. In the chest CT, consolidation was observed in 5 cases, a mass-like shadow in 4, a central low attenuation area (LAA) in 7, and bronchial and bronchiolar dilatation in 6. In the pathological findings, all cases showed bronchial dilatation and abscess formation in the bronchi, as well as peribronchial granulation. The evaluation of radiological and pathological correlation revealed that the central LAA in the chest CT corresponded to the abscess formation composing of actinomyces, and the cavity corresponded to the bronchial dilatation. These results suggest that radiological findings, such as LAA and bronchial and bronchiolar dilatation, are characteristic for TA, and can be useful in making a diagnosis of TA.