Читать книгу Respiratory Medicine - Stephen J. Bourke - Страница 111

Cavitation is the presence of an area of radiolucency within a mass lesion. It is a feature of bronchial carcinoma (particularly squamous carcinoma) (Fig. 4.8), tuberculosis, lung abscess, pulmonary infarcts, granulomatosis with polyangiitis (GPA) and some pneumonias (e.g. Staphylococcus aureus, Klebsiella pneumoniae).

Figure 4.4 Left lower lobe collapse. The left lower lobe has collapsed medially and posteriorly and appears as a dense white triangular area behind the heart close to the mediastinum. The remainder of the left lung appears hyperlucent because of compensatory expansion. Bronchoscopy showed an adenocarcinoma occluding the left lower lobe bronchus.

Figure 4.5 Left lung collapse. There is complete opacification of the left hemithorax with shift of the mediastinum to the left. Bronchoscopy showed a small cell carcinoma occluding the left main bronchus.

Figure 4.6 The silhouette sign, showing abnormal lung shadowing in the left lower zone. Where the sharp outline of mediastinal structures or diaphragm is lost because of normal lung opacification, it can be concluded that the shadow is immediately adjacent to the structure (and vice versa). In example (a), the shadow must be anterior and next to the heart as the sharp outline of the heart is lost. In (b), it must be posterior, as the heart outline is preserved.

Table 4.1 Causes of pulmonary masses

NeoplasticPrimary bronchial carcinomaMetastatic carcinomaBenign tumours (hamartoma)

Non‐neoplasticTuberculomaLung abscessHydatid cystPulmonary infarctArteriovenous malformationEncysted interlobar effusion (‘pseudotumour’)Rheumatoid nodule