Idiopathic nonspecific interstitial pneumonia: report of an American Thoracic Society project.
BACKGROUND
The 2002 American Thoracic Society/European Respiratory Society classification of idiopathic interstitial pneumonias identified nonspecific interstitial pneumonia (NSIP) as a provisional diagnosis. Concern was expressed that NSIP was a "wastebasket" category, difficult to distinguish from other idiopathic interstitial pneumonias.


OBJECTIVE
The following questions were addressed: (1) Is idiopathic NSIP a distinct entity? 2) If so, what are its clinical, radiologic and pathologic characteristics? (3) What is the role of radiology and pathology in establishing the diagnosis? (4) To make a diagnosis of idiopathic NSIP, what other disorders need to be excluded and how should this be done?


METHODS
Investigators who had previously reported cases of idiopathic NSIP were invited to submit cases for review (n = 305). After initial review, cases with complete clinical, radiologic, and pathologic information (n = 193) were reviewed in a series of workshops.


RESULTS
Sixty-seven cases were identified as NSIP. Mean age was 52 years, 67% were women, 69% were never-smokers, and 46% were from Asian countries. The most common symptoms were dyspnea (96%) and cough (87%); 69% had restriction. By high-resolution computed tomography, the lower lung zones were predominantly involved in 92% of cases; 46% had a peripheral distribution; 47% were diffuse. Most showed a reticular pattern (87%) with traction bronchiectasis (82%) and volume loss (77%). Lung biopsies showed uniform thickening of alveolar walls with a spectrum of cellular to fibrosing patterns. Five-year survival was 82.3%.


CONCLUSIONS
Idiopathic NSIP is a distinct clinical entity that occurs mostly in middle-aged women who are never-smokers. The prognosis of NSIP is very good.
Travis
William D
WD
Attending Thoracic Pathologist, Department of Pathology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA. travisw@mskcc.org
Hunninghake
Gary
G
King
Talmadge E
TE
Lynch
David A
DA
Colby
Thomas V
TV
Galvin
Jeffrey R
JR
Brown
Kevin K
KK
Chung
Man Pyo
MP
Cordier
Jean-François
JF
du Bois
Roland M
RM
Flaherty
Kevin R
KR
Franks
Teri J
TJ
Hansell
David M
DM
Hartman
Thomas E
TE
Kazerooni
Ella A
EA
Kim
Dong Soon
DS
Kitaichi
Masanori
M
Koyama
Takashi
T
Martinez
Fernando J
FJ
Nagai
Sonoko
S
Midthun
David E
DE
Müller
Nestor L
NL
Nicholson
Andrew G
AG
Raghu
Ganesh
G
Selman
Moisés
M
Wells
Athol
A
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D017678:Sex Distribution; D015996:Survival Rate; D014057:Tomography, X-Ray Computed