Organizing pneumonia/non-specific interstitial pneumonia overlap is associated with unfavorable lung disease progression.
BACKGROUND
Overlapping forms of interstitial pneumonia have been recognized, but are likely underappreciated, and their clinical, radiologic, and histologic characteristics are not well-defined.


METHODS
We identified 38 patients with surgical lung biopsy demonstrating histologic organizing pneumonia (OP) or histologic organizing pneumonia/non-specific interstitial pneumonia overlap (OP/NSIP) who met established multi-disciplinary clinical-radiologic-histologic criteria for OP. For each patient, radiologic and co-histologic findings were assessed, and clinical outcome was characterized as disease resolution (complete or near-complete resolution of radiologic opacities and absence of chronic respiratory symptoms) or unfavorable disease progression (death due to respiratory failure or forced vital capacity < 70% predicted > six months from diagnosis).


RESULTS
Seven of 38 patients had clinical-radiologic-histologic focal OP. Focal OP was associated with histologic OP (p = 0.019), and all seven patients demonstrated disease resolution. In the remaining 31 patients with cryptogenic or autoimmune-associated OP, 21 patients had histologic OP/NSIP, and 10 had histologic OP. Histologic OP/NSIP was associated with ground glass opacity (GGO, p = 0.012), reticulation (p = 0.029), traction bronchiectasis (p = 0.029), reactive pneumocytes (p = 0.013), and unfavorable disease progression (p < 0.0001). Histologic OP was associated with consolidation (p = 0.028) and disease resolution (p < 0.0001). Multivariate analysis demonstrated histologic OP/NSIP (p < 0.001) and radiologic GGO (p = 0.041) to be independently associated with unfavorable disease progression.


CONCLUSIONS
OP/NSIP overlap, either idiopathic or autoimmune-associated and identified by histologic and radiologic findings, was associated with unfavorable disease progression, and should therefore be recognized as a characteristic clinical-radiologic-histologic entity.
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; Baltimore VA Medical Center, Baltimore, MD, USA. Electronic address: ntodd@medicine.umaryland.edu.
Nevins W
NW
Todd
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
Ellen T
ET
Marciniak
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
Ashutosh
A
Sachdeva
Department of Diagnostic Radiology, University of Maryland School of Medicine, Baltimore, MD, USA.
Seth J
SJ
Kligerman
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Diagnostic Radiology, University of Maryland School of Medicine, Baltimore, MD, USA.
Jeffrey R
JR
Galvin
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; Baltimore VA Medical Center, Baltimore, MD, USA.
Irina G
IG
Luzina
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; Baltimore VA Medical Center, Baltimore, MD, USA.
Sergei P
SP
Atamas
Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.
Allen P
AP
Burke
D000368:Aged; D001327:Autoimmune Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D001706:Biopsy; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
Ground glass opacity; Non-specific interstitial pneumonia; Organizing pneumonia; Reticulation; Traction bronchiectasis