대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Courtesy

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Imaging Findings

PA chest shows lobar consolidation in right lower lung field. Ill-defined patchy opacity is noted in right upper lobe.

Chest CT shows enhancing consolidation with multiple low attenuation areas. In lower section, the lesion spreads along the pleura. Pleural enhancement is also seen.

Discussion

Most patients with nocardiosis have weakened immune systems because of corticosteroid use, immunosuppressive regimens for organ transplants, chemotherapy for malignancy, diabetes mellitus, congenital immune deficiencies or AIDS.

The pathologic features of pulmonary nocardiosis include a suppurative response, a granulomatous response, or a combination of the two.

Necrotizing abscesses may be either sharply circumscribed or not encapsulated. Granulomata, with or without central necrosis, may lack giant cells or epithelioid cells. Fibrosis or a chronic localized pleura-based pneumonia occurs in indolent infections of some mildly immunocompromised patients.

Nocardiae may spread locally with rib destruction and sinus tract formation and may metastasize to the central nervous system or elsewhere.


The most common radiographic abnormality is localized consolidation with or without cavitation.

Other manifestations include pleural effusion, nodules, and cavitary masses representing necrotizing pneumonia.

CT was better able to document the exact location and extent of the lesion, to differentiate a pulmonary lesion from a pleural lesion, and aid tissue sampling by fluoroscopy or ultrasonographic guidance.

In addition, there are cavities or low attenuation areas with enhancing rims that may represent a necrotizing tendency or abscess formation on CT.


Pleuropulmonary actinomycosis must be included in the differential diagnoses of nocardiosis.

Although pulmonary actinomycosis is most common in alcoholic person and patients with chronic obstructive lung disease, most infections occur in persons who are not immunocompromised.

Reference

1. Yoon HK, Im J-G, Ahn JM, Han MC. Pulmonary nocardiosis: CT findings. J Comput Assist Tomogr 1995; 19: 52-55.
2. Buckley JA, Padhani AR, Kuhlman JE. CT features of pulmonary nocardiosis. J Comput Assist Tomogr 1995; 19: 726-732

Keywords

Lung, Infection, Bacterial infection,