Honeycombing in Idiopathic Pulmonary Fibrosis: Pathology and Imaging Correlations
Lauren Xu, Seth Kligerman, Allen Burke. University of Maryland Medical Center, Baltimore, MD
Background: The pathologic features of honeycombing in idiopathic pulmnonary fibrosis (IPF) have not been well correlated with CT imaging findings.
Design: We compared histologic features with CT scans from 48 patients with usual interstitial pneumonia (UIP). CT scans were evaluated for multiple parameters, including honeycombing and ground glass opacities. The explanted lungs were inflated with formalin, and representative peripheral and central sections were taken with areas of cystic change. Areas of remodeling were classified histologically as dilated single cysts lined in part by respiratory epithelium and by fibroblast foci (respiratory cysts), fibrotic clusters of compressed cysts lined in part by respiratory epithelium (lobular remodeling), cysts lined by fibrous tissue and macrophage giant cells (septal emphysema), and bronchiectasis (bronchioles extending to within 1 cm of the peripheral pleura). In addition, areas of uniform small cysts, <1 mm, lined by reactive pneumoyctes with minimal interstitial fibrosis were semiquantated as NSIP-like areas. Subpleural cystic spaces > 2mm and areas of lobular remodeling were measured morphometrically.
Results: There were 63 lungs from 48 patients (33 men, 65 ± 11 years, 14 women, 65 ± 10 years). Histologically, respiratory cysts were observed in 30 explants (63%), septal emphysema in 10 (21%), and bronchiectasis in 25 (52%). Lobular remodeling was extensive in 22 (46%). NSIP-like areas were present in 24 (50%), and extensive in 22 (46%). CT determined honeycombing showed a positive correlation with respiratory cysts (p=.03), bronchiectatic cysts (p=.02), and all cysts combined (p=.004). Ground glass opacity was positively associated with NSIP-like areas (p=.0002), and not other parameters. Morphometrically, bronchiectatic cysts measured 3.7 ± 1.6 mm; respiratory-lined cysts 3.8 ± 1.8 mm; giant cell-lined cysts 6.3 ± 2.8 mm; and lobular remodeling nodules 3.8 ± 1.2 mm.
Conclusions: Honeycombing by CT is associated with heterogeneous pathological findings. In patients with IPF, ground glass opacity is correlated with NSIP-like areas histologically.
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 283, Tuesday Afternoon