Figure 22.

A-C, Secondary organizing pneumonia (OP): radiologic-pathologic correlation. A, On a surgical lung biopsy specimen, this patient with Sjögren syndrome had the cellular nonspecific interstitial pneumonia (NSIP) pattern as the predominant lesion. There is a diffuse, moderate cellular interstitial infiltrate of lymphocytes and plasma cells causing mild thickening of the alveolar walls. There are many lymphoid aggregates (arrows). B, Focal areas show OP with polypoid plugs of loose connective tissue in the distal airways (arrows). C, An axial CT scan obtained with the patient prone demonstrates peribronchial areas of consolidation with air bronchograms characteristic of OP. Also noted are bilateral ground-glass opacification and mild reticulation suggestive of NSIP. Surgical biopsy results showed predominant NSIP and mild focal OP. The extent of OP was underestimated on the biopsy specimen, presumably because it is peribronchial and away from the pleura, whereas the NSIP pattern also involves the subpleural regions. The radiologic-pathologic correlation in this case indicated the CT scanning findings trumped the surgical lung biopsy findings, and in this clinical setting secondary OP associated with Sjögren syndrome was diagnosed.