The Histopathology of End Stage Pulmonary Sarcoidosis: Comparison of 11 Explanted Lungs with Usual Interstitial Pneumonia
Chen Zhang, Kevin Chan, Heather Ames, Jeffrey Myers, Lindsay Schmidt. University of Michigan, Ann Arbor, MI
Background: Sarcoidosis is an idiopathic multi-system disease that commonly affects the respiratory tract and is characterized by nonnecrotizing epithelioid granulomas. In 10 to 30% of cases the lungs undergo progressive fibrosis resulting in respiratory failure. Pathologic features of end stage pulmonary sarcoidosis (ESPS) have not been well described; anecdotal reports have suggested that it may mimic usual interstitial pneumonia (UIP). We hypothesized that ESPS has distinct histologic features.
Design: We identified 11 patients with a clinical diagnosis of ESPS who underwent lung transplantation between 1995 and 2012. Controls were 10 age and sex matched lung transplant patients with UIP (IPF=8; systemic lupus erythematosis=2). H&E-stained sections of each case were examined for the following features: extent/pattern of fibrosis; presence/quantity (per 10 high power fields) of fibroblastic foci and granulomas; distribution and morphology of granulomas; presence of granulomas in hilar lymph nodes; presence/extent of honeycomb change; bronchiectasis; hypertensive vascular change. Extent of fibrosis and honeycomb change were scored as follows: 1=1-25%; 2=26-50%; 3=51-75%; 4=76-100% of lung parenchyma.
Results: Well-formed granulomas with a lymphangitic distribution (visceral pleura, bronchovascular bundles, and interlobular septa) were seen in all ESPS cases, but none of the control cases. Granulomas were present in hilar lymph nodes from 9 of 9 ESPS cases, and none of 8 control cases. Ten of 11 ESPS cases showed patchy fibrosis with a lymphangitic distribution; 7 of 10 control cases showed patchy fibrosis but in a random distribution. One of the 11 ESPS cases showed diffuse fibrosis, while diffuse fibrosis was seen in 3 of 10 control cases (9% vs 30%, p<0.05). The average extent of fibrosis was significantly lower in ESPS cases, as compared with that in control cases (2.5 ± 0.5 vs 3.5 ± 0.5, p<0.05). There was no significant difference in honeycomb changes, fibroblastic foci, bronchiectasis and hypertensive vascular changes between the ESPS group and control group.
Conclusions: ESPS and UIP have distinct histopathologic features in explanted lungs. ESPS is characterized by a combination of well-formed granulomas and a lymphangitic pattern of fibrosis that differs from the patchwork pattern of fibrosis seen in UIP. Granulomas in hilar lymph nodes are limited to patients with ESPS.
Monday, March 4, 2013 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 297, Monday Morning