Cystic change was identified as the sole HRCT abnormality in three cases. Ground-glass attenuation was detected on HRCT in three patients (Table 2). Emphysema was detected in two cases on HRCT (14%). Mild sub-carinal and pretracheal adenopathy (1 to 2 cm) was detected on the CT in three cases (21%).
Radiographic, Histologic, and Functional Correlates of RB/DIP in PLCH in the Study Population
All biopsy specimens showed diagnostic lesions of PLCH. Histopathologic evidence of RB/DIP-like changes were identified in all biopsy specimens (Table 1), with the extent of involvement ranging from 10 to 80% of the biopsy specimen. Separate review of chest HRCTs identified three cases with ground-glass attenuation in a random distribution (Table 2), two of which were found to have extensive RB/DIP-like changes (70 to 80%) on histologic examination, indicating that in these cases, the presence of extensive associated RB/DIP-like changes may have resulted in the radiographic appearance of ground-glass attenuation. The provisional diagnosis (and differential) based on the HRCT findings in these three cases associated with ground-glass attenuation did not include PLCH but favored hypersensitivity pneumonitis (Table 2). Although several cases demonstrated moderate-to-extensive (> 60%) RB/ DIP-like changes on biopsy (Table 1), ground-glass attenuation was detected in only two of these cases and another case with mild (20%) histologic involvement. other
Data regarding cumulative pack-years smoked at the time of lung biopsy were available from 13 patients. The cumulative amount of pack-years smoked at the time of diagnosis correlated with the extent of RB/DIP-like changes scored by the pathologist (Fig 2; r = 0.61, p = 0.027). A strong positive correlation was also found between the cumulative pack-years of cigarettes smoked and the extent of alveolar septal fibrosis detected on biopsy specimens (r = 0.86, p = 0.001).
Figure 2. Correlation of cumulative pack-years smoked at the time of lung biopsy with the extent of RB/DIP-like change.