Sarcoid Lung Disease: Pathologic Findings at Explant with Imaging Correlation
Natasha Grandhi, Seth Kligerman, Allen Burke. University of Maryland Medical Center, Baltimore, MD
Background: Sarcoid granulomas typically occur in a lymphatic distribution in the lung. A subset of patients may develop lung failure due to fibrosis. CT findings of patterns of fibrosis have not been studied in detail.
Design: We retrospectively evaluated histologic sections from 10 lung explants in a patient with a clinical diagnosis of sarcoid lung disease (SLD). Each lung was sectioned in a systematic fashion by the same pathologist sampling central and peripheral sections from each lobe. In 9 patients, high-resolution CT scans were available for correlation.
Results: Histologically, 7 of 10 explants showed findings typical of SLD (granulomas and fibrosis in a lymphatic distribution); 2 showed dense scarring with elastosis in a sarcoid-like distribution without granulomas (atypical sarcoid). The 10th case showed incidental SLD (granulomas without fibrosis) in a setting of organizing pneumonia interstitial lung disease (cryptogenic organizing pneumonia, COP). The 9 patients with SLD were 7 women (51 ± 12 years) and 2 men (48 ± 4 years). Of the 7 cases with typical sarcoid, 4 had numerous granulomas, in the bronchial submucosa, peribronchial regions, and interstitium. Three had relatively sparse granulomas embedded in dense scar. Of the 9 cases with typical or atypical sarcoid, 6 cases showed microscopic areas of NSIP up to 1 cm in size, and 2 peripheral honeycombing; however, none showed an overall pattern resembling NSIP or usual interstitial pneumonia (UIP). Bronchiectasis was seen in every case and large cysts (up to 7 mm) lined by respiratory epithelium and surrounded by scar were characteristic and seen in 6 of the 9 cases.
Of the 7 lungs with typical sarcoid, 3 CTs were evaluated as definite sarcoid, and 3 probable (one CT not available). The 2 atypical sarcoid cases were evaluated by CT as definite, and one probable sarcoid. The case of COP was evaluated as probably not sarcoid on CT. Imaging demonstrated honeycombing bronchiectasis in all cases of definite or probable sarcoid, with possible honeycombing in 2 (one correlating with histologic findings).
Conclusions: SLD shows a fibrotic pattern that is distinct from UIP or NSIP, and is composed of dense fibrosis with bronchiectasis and large cysts lined by respiratory epithelium. There is a good correlation with high resolution CT. Granulomas amenable to biopsy (in the peribronchiolar interstitium or bronchial submucosa) were present in 4 of 9 cases of presumed sarcoid; in the others they were scarce or absent, related to advanced scarring.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 299, Wednesday Morning