대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pulmonary actinomycosis

Radiologic Findings

Fig 1. Initial chest PA shows multiple nodular opacities in both lungs.
Fig 2-5. Enhanced chest CT images demonstrate multiple cavitary nodules in both lungs. The central portion of the cavitary nodules contains necrotic low-attenuation change.

A CT-guided biopsy was performed for the nodule, and the results were compatible with actinomycosis

Brief Review

Thoracic actinomycosis is an uncommon, chronic suppurative bacterial infection caused by actinomyces species, especially Actinomyces israelii. It is usually seen in immunocompetent patients with respiratory disorders, poor oral hygiene, alcoholism, and chronic debilitating diseases. Detection of ‘sulfur’ granules by gram or histologic staining is the principal method of direct detection of Actinomyces.

Parenchymal patterns of pulmonary actinomycosis include peripheral pulmonary nodules, masses, or consolidations, all of which may or may not be cavitary or multifocal. Typical CT findings are reported as central areas of low attenuation within the consolidation in 62-75% of cases and adjacent pleural thickening in 50-73%. The disease initially manifests as a small, poorly defined, peripheral pulmonary nodule with or without interlobular septal thickening. The pulmonary nodule gradually increases to segmental air-space consolidation, which suggests the bronchogenic spread of the disease. Central low-attenuation areas may be multiple and variable in size and show rim-like peripheral enhancement on enhanced CT. Histologically, central low-attenuation areas seen on CT represent microabscesses, which contain actinomycotic or sulfur granules. The peripheral enhancing portion is composed of an outer rim of granulation tissue and fibrosis. Differential diagnoses of the parenchymal type include tuberculosis, bacterial or fungal necrotizing pneumonia, and lung cancer.

The principal treatment of actinomycosis is long-term use of high-dose intravenous penicillin. The course of the disease depends largely on adequate and early antibiotic therapy.

Please refer to

Case 10, Case 174, Case 324, Case 412, Case 521, Case 820, Case 858, Case 1001, Case 1100,

KSTR Imaging Conference 2004 Summer  Case 6 ,
KSTR Imaging Conference 2009 Spring  Case 2 ,
KSTR Imaging Conference 2011 Summer  Case 8 ,
KSTR imaging conference 2017 Summer  Case 14,

References

1. Han JY, Lee KN, Lee JK, et al. An overview of thoracic actinomycosis: CT features. Insights Imaging 2013;4:245-252.
2. Kim TS, Han J, Koh W, et al. Thoracic Actinomycosis: CT Features with Histopathologic Correlation. AJR 2006;186:225-231.

Keywords

lung, pulmonary actinomycosis,