Pulmonary Sarcoidosis

Fig. 18.11 Pulmonary sarcoidosis depicting perilymphatic nodules in a 36-year-old man. (a) Lung window images of CT (2.5-mm section thickness) scan obtained at level of distal bronchus intermedius show small nodules along bronchovascular bundles (arrows), subpleural lungs (open arrows), and in centrilobular areas (curved arrows). (b) High-magnification (×200) photomicrograph of transbronchial lung biopsy specimen obtained from lingular division of left upper lobe discloses noncaseating granulomas (arrows) located along bronchiole

interstitial tissue of the interlobular septa and pleura. On histopathologic analysis, pneumoconiosis nodules are composed of mature collagen in the central portion, with a peripheral zone of particle-laden macrophages [40] (Fig. 18.10). Therefore, nodules of pneumoconiosis appear as well-circumscribed nodules with perilymphatic distribution on TSCT.

Patient Prognosis

Patients should generally be removed from further exposure. No proven curative treatment for pneumoconiosis exists. Bronchodilators are considered for symptomatic patients with airflow obstruction. Pneumothorax, cor pulmonale, and respiratory failure should be managed separately.

The presence of small nodules with perilymphatic distribution is the most common parenchymal disease pattern seen in patients with pulmonary sarcoidosis [44] (Figs. 18.9 and 18.11). TSCT shows sharply defined small (2–4 mm in diameter), rounded nodules, usually with a bilateral and symmetric distribution, predominantly but not invariably in the upper and middle zones. The nodules are found most often in the subpleural and peribronchovascular interstitium and less often in the interlobular septa. Sarcoid nodules may coalesce over time, forming large nodules. Other findings include reticulonodular pattern, parenchymal consolidation, ground-glass opacity, and fibrocystic changes [45].

CT–Pathology Comparisons

Correlation of TSCT with pathologic findings has shown that sarcoid nodules represent interstitial aggregates of granulomas and associated fibrous tissue [46]. Large nodules represent coalescent granulomas. Ground-glass opacity represents an accumulation of many granulomatous lesions, with or without fibrosis, in the alveolar septa and around the small vessels.

Patient Prognosis

Treatment of pulmonary sarcoidosis is usually limited to the symptomatic patients. Corticosteroids remain as the principal