Correct!
2. A fibrotic non-specific interstitial pneumonia pattern
The bilateral, basal and subpleural predominant reticulation associated with ground-glass opacity, architectural distortion, and traction bronchiectasis seen on the thoracic CT represents a fibrotic non-specific interstitial pneumonia (NSIP) pattern. This pattern can also be seen with “early” usual interstitial pneumonia (UIP), although the UIP pattern is considered to be present when honeycomb cysts are seen in the context of the aforementioned findings. The “organizing pneumonia” (OP) pattern consists of multifocal, typically bilateral, areas of peripheral, often frankly subpleural, consolidation, possibly with areas of ground-glass opacity, often also showing a peribronchial distribution as well. Occasionally the CT findings may be migratory and/or recurrent in patients with OP. Recognized variations of the OP pattern include areas of perilobular consolidation, the “reverse ground-glass halo” sign (also referred to as the “atoll” sign), and solitary or multiple nodules that may show air bronchograms. Rarely OP may present as reticular abnormalities with architectural distortion and traction bronchiectasis at thoracic CT and may closely resemble the fibrotic NSIP pattern. A number of thoracic CT appearances for lymphocytic interstitial pneumonia (LIP) have been described, and there is no specifically recognized “LIP pattern” in the same sense as described for NSIP, UIP, and OP. The main thoracic CT patterns described in patients with LIP include areas of ground-glass opacity and ground-glass opacity centrilobular nodules, possibly with interlobular septal thickening, perilymphatic nodules, and multiple randomly distributed thin-walled cysts; the latter pattern is often discussed as the most “recognizable” thoracic CT pattern of LIP, although the appearance is ultimately non-specific and can be closely mimicked by lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, and various causes of small airway obstruction. The “crazy-paving” pattern at thoracic CT represents “thickened interlobular septa and intralobular
lines superimposed on a background of ground-glass opacity, resembling irregularly shaped paving stones. The crazy-paving pattern is often sharply demarcated from more normal lung and may have a geographic outline.” This pattern has been classically associated with pulmonary alveolar proteinosis, but is not completely specific for that disorder and has been described in a number of conditions.
Which of the following represents the most appropriate next step for the management of this patient? (Click on the correct answer to proceed to the fourth of eight pages)