Persistent lobar consolidation: Diagnostic considerations

The radiographic appearance of pulmonary opacities reflects the underlying anatomic structure and anatomic considerations influencing disease spread. Recognition of these considerations allows one pattern of pulmonary opacity often encountered at chest radiography, consolidation, to be grouped into air space and bronchopneumonia patterns. Pulmonary infection is the primary diagnostic consideration when consolidation is encountered, although noninfectious etiologies require consideration in certain situations. The primary noninfectious consideration for an air space pattern on chest radiography is bronchioloalveolar carcinoma, although this bronchogenic neoplasm may present in a number of different ways on thoracic imaging. The most common presentation of bronchioloalveolar carcinoma is the solitary pulmonary nodule with less common manifestations, including multifocal nodular or segmental/lobar ground-glass opacity or consolidation. The latter presentation frequently resembles pneumonia. Recognition of these presentations is important, especially in patients with radiographic abnormalities that suggest pneumonia but fail to resolve with appropriate treatment.