DOI:10.2214/AJR.05.1826
AJR 2007; 188:334-344
© American Roentgen Ray Society
Hypersensitivity Pneumonitis: Spectrum of High-Resolution CT and Pathologic Findings
C. Isabela S. Silva1,
Andrew Churg2 and
Nestor L. Müller1
1 Department of Radiology, Vancouver General Hospital, University of British
Columbia, 899 W 12th Ave., Vancouver, BC, Canada V5Z 1M9.
2 Department of Pathology, Vancouver General Hospital, University of British
Columbia, Vancouver, BC, Canada V5Z 1M9.
Received October 18, 2005;
accepted after revision December 7, 2005.
Address correspondence to C. I. S. Silva
(isabela.silva{at}vch.ca).
Abstract
OBJECTIVE. The purpose of this article is to illustrate the spectrum
of pathologic and high-resolution CT features of hypersensitivity pneumonitis
(HP).
CONCLUSION. High-resolution CT plays an important role in the
diagnosis of HP. A confident diagnosis of subacute HP is based on the presence
of ground-glass opacities, poorly defined centrilobular nodules, and mosaic
attenuation on inspiratory images and of air trapping on expiratory CT images.
Chronic HP is characterized on high-resolution CT by the presence of
reticulation due to fibrosis superimposed on findings of subacute HP.
Histologically, subacute HP is characterized by the presence of cellular
bronchiolitis, noncaseating granulomas, and bronchiolocentric lymphocytic
interstitial pneumonitis. Areas of organizing pneumonia also may be seen. The
high-resolution CT and pathologic features of chronic HP frequently overlap
with those of nonspecific interstitial pneumonia and usual interstitial
pneumonia. Awareness of the various manifestations of HP is important for
early diagnosis and management.
Keywords: high-resolution CT • hypersensitivity pneumonitis • interstitial lung disease • lung • lung disease
Introduction
Hypersensitivity pneumonitis (HP) is a diffuse granulomatous
interstitial lung disease caused by inhalation of various antigenic organic
particles [1]. HP is often
difficult to diagnose because the clinical manifestations are nonspecific and
the radiologic and histologic patterns can mimic those of other interstitial
and small airway diseases [2].
HP traditionally has been classified as manifesting in three phases: acute,
subacute, and chronic. Although this classification is helpful, patients often
present with both subacute and chronic findings
[1,
3]. Acute HP is characterized
by abrupt onset of symptoms within a few hours after heavy antigen exposure in
a previously sensitized patient. Subacute HP is caused by intermittent or
continuous exposure to low doses of antigen. Chronic HP results from very
low-level persistent or recurrent exposure to antigen and is differentiated
from subacute HP by the presence of fibrosis
[1,
3].
A high index of suspicion and meticulous acquisition of an environmental
and occupational history are essential in making the diagnosis. In as many as
40% of histologically proven cases of HP, however, the offending agent is not
identified [4,
5]. High-resolution CT plays an
important role in the diagnosis of HP and frequently shows characteristic
findings in patients with normal chest radiographic findings
[4]. Early recognition of the
disease and prevention of long-term antigen exposure are necessary to avoid
progression to irreversible fibrosis
[5]. The aim of this pictorial
essay is to illustrate the spectrum of high-resolution CT and pathologic
findings of HP.
Histologic Findings
Acute HP is characterized histologically by the presence of neutrophilic
infiltration of the respiratory bronchioles and alveoli. A pattern of diffuse
alveolar damage and temporally uniform, nonspecific, chronic interstitial
pneumonitis may also be seen
[1,
3]. Subacute HP is
characterized histologically by the presence of cellular bronchiolitis,
noncaseating granulomas, and bronchiolocentric interstitial pneumonitis with a
predominance of lymphocytes (Fig.
1A,
1B). Areas of organizing
pneumonia (bronchiolitis obliterans with organizing pneumonia) may be
identified [6]. These findings,
however, are not present in all cases. Furthermore, in some patients the
predominant histologic pattern is nonspecific interstitial pneumonia (NSIP) or
usual interstitial pneumonia (UIP). Ohtani et al.
[6] analyzed the histologic and
clinical characteristics of chronic bird fancier's lung in 26 patients. The
NSIP pattern was found in 13 patients, eight of them having fibrotic NSIP-like
lesions; the UIP-like pattern in 11 patients; and organizing pneumonia
(bronchiolitis obliterans with organizing pneumonia reaction) in two
patients.
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Fig. 1A —35-year-old woman with subacute hypersensitivity pneumonitis (bird
fancier's lung). Photomicrograph of histopathologic specimen obtained at
surgical lung biopsy shows moderate, diffuse, bronchiolocentric chronic
lymphocytic inflammatory infiltrate. (H and E, x60)
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Fig. 1B —35-year-old woman with subacute hypersensitivity pneumonitis (bird
fancier's lung). Magnified view of different area from A shows poorly
formed granuloma (arrows) and chronic interstitial inflammatory
infiltrate. (H and E, x200)
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In the presence of a history of exposure and consistent clinical and
radiologic findings, the diagnosis of HP can be confirmed by visualization of
increased numbers of lymphocytes in bronchoalveolar lavage fluid and
occasionally by findings at transbronchial biopsy. Surgical biopsy, however,
is often needed for the definitive diagnosis of both subacute and chronic HP
and for reliable differentiation of chronic HP from idiopathic interstitial
pneumonia [3,
4].
High-Resolution CT Findings
The radiologic manifestations of acute HP are those of acute pulmonary
edema. Because of the characteristic clinical manifestations and the rapid
resolution of the symptoms, high-resolution CT is seldom performed in the
evaluation of these patients
[1,
7]. The characteristic
high-resolution CT manifestations of subacute HP consist of patchy or diffuse
bilateral ground-glass opacities, poorly defined small centrilobular nodules,
and lobular areas of decreased attenuation and vascularity on inspiratory
images and of air trapping on expiratory images (Figs.
2A,
2B and
3). The ground-glass opacities
primarily reflect the presence of diffuse lymphocytic interstitial
pneumonitis; minor degrees of organizing pneumonia, when present, also can
contribute to this appearance (Fig.
4). The poorly defined centrilobular nodules may be caused by
cellular bronchiolitis, the predominantly peribronchiolar distribution of
interstitial pneumonitis (Fig.
1A,
1B), or focal areas of
organizing pneumonia (Fig. 5).
The lobular areas of decreased attenuation and air trapping are presumably
caused by small-airway obstruction by cellular bronchiolitis or, less
commonly, by constrictive bronchiolitis
[3,
7].
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Fig. 2A —41-year-old man with subacute hypersensitivity pneumonitis.
High-resolution CT image shows bilateral poorly defined centrilobular nodules
and ground-glass opacities. Also evident are lobular areas (arrows)
of decreased attenuation.
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Fig. 2B —41-year-old man with subacute hypersensitivity pneumonitis.
Expiratory high-resolution CT scan at same level as A shows air
trapping in lobules (curved arrows) that had decreased attenuation on
inspiratory CT and in other lung regions (straight arrow).
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Fig. 3 —36-year-old woman with hypersensitivity pneumonitis caused by
selective serotonin reuptake inhibitor sertraline. High-resolution CT image
shows bilateral ground-glass opacities and lobular areas (arrows) of
decreased attenuation and vascularity. Patient was taking oral sertraline for
management of depressive illness.
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Fig. 4 —74-year-old man with hypersensitivity pneumonitis (bird fancier's
lung). Lowpower view of surgical lung biopsy specimen shows mild interstitial
mononuclear cell infiltrate that correlates with areas of ground-glass
opacities seen on highresolution CT. (H and E, x60)
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Fig. 5 —65-year-old man with hypersensitivity pneumonitis (bird fancier's
lung). Photomicrograph of surgical lung biopsy specimen shows chronic
inflammatory infiltrate with focal area (arrows) of organizing
pneumonia. (H and E, x60)
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Chronic HP is characterized on high-resolution CT by the presence of
reticulation and traction bronchiectasis and bronchiolectasis due to fibrosis
superimposed on findings of acute or subacute HP
[7] (Fig.
6A,
6B,
6C,
6D). The reticulation in
chronic HP can be patchy or random or have a predominantly subpleural and
peribronchovascular distribution but typically tends to spare the lung bases
[7,
8]. In a small percentage of
cases, chronic HP results in subpleural honeycombing
[3,
7] (Fig.
7A,
7B,
7C).
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Fig. 6A —65-year-old man with chronic and subacute hypersensitivity
pneumonitis due to exposure to red cedar. High-resolution CT image at level of
left upper bronchus shows bilateral patchy areas of ground-glass opacities,
fine reticulation, and traction bronchiectasis (arrow). Bilateral
centrilobular nodules (circles) also are evident.
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Fig. 6B —65-year-old man with chronic and subacute hypersensitivity
pneumonitis due to exposure to red cedar. High-resolution CT image at level of
lung bases shows relative sparing with minimal reticulation. Lobules
(arrows) with decreased attenuation and vascularity are evident in
lower lobes.
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Fig. 6C (continued) —65-year-old man with chronic and subacute hypersensitivity
pneumonitis due to exposure to red cedar. Low-power view of surgical lung
biopsy specimen shows areas of subacute (curved arrows) and chronic
(straight arrows) changes of hypersensitivity pneumonitis. (H and E,
x40)
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Fig. 6D (continued) —65-year-old man with chronic and subacute hypersensitivity
pneumonitis due to exposure to red cedar. Higher-power view shows chronic
interstitial inflammatory infiltrate and interstitial fibrosis. Also evident
are giant cell (curved arrow) and fibroblast focus (straight
arrows). (H and E, x400)
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Fig. 7A —56-year-old man with chronic hypersensitivity pneumonitis due to
occupational exposure to isocyanate compounds in paint. High-resolution CT
scan shows bilateral reticulation, traction bronchiectasis (curved
arrow), and traction bronchiolectasis (straight arrows). Also
evident are subpleural cysts consistent with mild honeycombing
(arrowheads). Area of ground-glass opacity with superimposed
reticulation is present in right middle lobe. These high-resolution CT
findings resemble those of nonspecific interstitial pneumonia.
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Fig. 7B —56-year-old man with chronic hypersensitivity pneumonitis due to
occupational exposure to isocyanate compounds in paint. Coronal reformatted
image shows predominance of abnormalities in subpleural and basal regions.
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Fig. 7C (continued) —56-year-old man with chronic hypersensitivity pneumonitis due to
occupational exposure to isocyanate compounds in paint. Photomicrograph of
surgical lung biopsy specimen shows nondiagnostic honeycombing and moderate
mononuclear interstitial infiltrate. (H and E, x20)
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Spectrum of High-Resolution CT Findings
Normal High-Resolution CT Findings
In a study by Lacasse et al.
[4], 16 (8%) of 199 patients
with proven HP underwent highresolution CT with images acquired at 10-mm
intervals and had normal findings. The prevalence of normal findings on
high-resolution CT scans is even higher when scans are obtained at greater
intervals. The findings on CT can be subtle or be confused with dependent
density (Fig. 8A,
8B).
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Fig. 8A —80-year-old woman with hypersensitivity pneumonitis due to exposure
to mold. High-resolution CT scan shows subtle ground-glass opacities and
minimal subpleural reticulation in dorsal regions of lower lobes that can be
interpreted as normal dependent density.
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Fig. 8B —80-year-old woman with hypersensitivity pneumonitis due to exposure
to mold. Prone high-resolution CT scan at same level as A shows
persistent abnormalities in dorsal regions of lower lobes. Diagnosis of
hypersensitivity pneumonitis was made clinically. Samples of air in patient's
apartment grew Penicillium organisms.
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Atypical Distribution of Ground-Glass Opacities
The ground-glass opacities of HP usually are extensive, bilateral, and
symmetric [7]. In some
patients, however, they are patchy or asymmetric
(Fig. 9). Fine reticulation
may be superimposed on the ground-glass opacities and mimic the findings of
NSIP on high-resolution CT (Fig.
7A,
7B,
7C) or at histologic
examination (Fig. 10A,
10B). HP should always be
considered a possible cause of a CT or histologic pattern of NSIP
[2,
3].
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Fig. 10A —53-year-old man with hypersensitivity pneumonitis. High-resolution
CT image shows extensive bilateral ground-glass opacities, poorly defined
small centrilobular nodules (straight arrows), and lobular areas
(curved arrows) of decreased attenuation and vascularity in right
middle lobe. These findings are characteristic of subacute hypersensitivity
pneumonitis.
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Fig. 10B —53-year-old man with hypersensitivity pneumonitis. Surgical lung
biopsy specimen of right lower lobe shows thickening of alveolar wall by mild
to moderate inflammation consisting mostly of lymphocytes and plasma cells.
Histologic findings are those of nonspecific interstitial pneumonitis.
Diagnosis of hypersensitivity pneumonitis was based on radiologic and clinical
findings. Patient had positive results for Aspergillus precipitins,
but specific etiologic agent for hypersensitivity pneumonitis was not
identified. (H and E, x40)
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Centrilobular Nodules
Small centrilobular nodules may be the predominant or only high-resolution
CT abnormality in patients with subacute HP
[4]. Although they usually are
numerous, the nodules can be few (Fig.
11) or have an atypical distribution
(Fig. 12). Irregular nodules
larger than 10 mm in diameter are uncommon and usually represent focal areas
of organizing pneumonia [3]
(Fig. 13).
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Fig. 11 —45-year-old woman with subacute hypersensitivity pneumonitis
(winemaker's lung). High-resolution CT image at level of right upper bronchus
shows bilateral small centrilobular nodules (arrows).
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Fig. 13 —55-year-old man with hypersensitivity pneumonitis due to exposure to
mold. High-resolution CT image of upper lobes shows patchy bilateral
ground-glass opacities, nodular areas of consolidation (straight
arrows), and perilobular opacities (curved arrows). These
high-resolution CT findings resemble those of organizing pneumonia
(bronchiolitis obliterans organizing pneumonia).
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Decreased Attenuation and Vascularity
Areas of decreased attenuation and vascularity with air trapping on
expiratory CT, often in a lobular distribution, represent indirect signs of
bronchiolar obstruction in HP
[3]. Although they are seen in
as many as 90% of patients, these findings usually are limited in extent
[7] (Fig.
14A,
14B).
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Fig. 14A —74-year-old man with chronic and subacute hypersensitivity
pneumonitis (bird fancier's lung). High-resolution CT image shows mild
reticulation and extensive bilateral ground-glass opacities. Also evident are
bilateral centrilobular nodules (straight arrows) and localized areas
(curved arrows) of decreased attenuation and vascularity.
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Fig. 14B —74-year-old man with chronic and subacute hypersensitivity
pneumonitis (bird fancier's lung). Surgical lung biopsy specimen shows
cellular bronchiolitis with infiltrate of chronic inflammatory cells
(straight arrows), thickening wall (curved arrows), and
narrowing lumen. This type of bronchiolitis presumably accounts for lobular
areas of decreased attenuation and vascularity seen on high-resolution CT. (H
and E, x160)
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Reticulation
HP can cause bilateral predominantly lower lung zone ground-glass opacities
with superimposed fine reticulation and traction bronchiectasis resembling
fibrotic NSIP [2] (Fig.
7A,
7B,
7C). It also can cause
bilateral reticulation and honeycombing in a predominantly subpleural and
basal distribution that resembles idiopathic pulmonary fibrosis
[2]. However, the centrilobular
nodules and lobular areas of air trapping typically seen in HP are uncommon in
idiopathic NSIP and idiopathic pulmonary fibrosis.
Airspace Consolidation
Consolidation in patients with HP can be caused by organizing pneumonia
(Fig. 13) or a superimposed
complication such as infection; less commonly it is caused by acute
exacerbation with diffuse alveolar damage. Diffuse alveolar damage is an
uncommon but potentially fatal complication of HP that can result from
extensive exposure to antigens in a sensitized patient. It also occasionally
occurs in patients who do not have apparent acute exposure (Fig.
15A,
15B).
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Fig. 15A —70-year-old woman with acute exacerbation of biopsy-proven chronic
hypersensitivity pneumonitis. High-resolution CT image at level of right upper
lobe shows patchy bilateral ground-glass opacities and peripheral
reticulation.
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Fig. 15B —70-year-old woman with acute exacerbation of biopsy-proven chronic
hypersensitivity pneumonitis. High-resolution CT image at same level as
A obtained 7 years after A when patient developed acute
exacerbation shows extensive bilateral ground-glass opacities.
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Cysts
Cysts have been reported in 13% of patients with subacute HP
[9]. The cysts are typically
few, range from 3 to 25 mm in diameter, and are associated with ground-glass
opacities (Fig. 16). The cysts
in HP resemble those of lymphoid interstitial pneumonia and, like the cysts of
lymphoid interstitial pneumonia, are presumably caused by partial bronchiolar
obstruction by the peribronchiolar lymphocytic infiltrate present in patients
with HP [9].
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Fig. 16 —45-year-old woman with subacute hypersensitivity pneumonitis.
Highresolution CT image shows bilateral ground-glass opacities, poorly defined
centrilobular nodules (straight arrows), and thin-walled cysts. Also
evident is lobular area (curved arrow) of decreased attenuation in
left upper lobe. Patient was lifelong nonsmoker. (Reprinted with permission
from [9])
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Emphysema
Most patients with chronic HP have evidence of fibrosis with reticulation
and traction bronchiectasis. Patients with chronic farmer's lung, however,
including lifelong nonsmokers, are more likely to develop emphysema than they
are interstitial fibrosis [10]
(Fig. 17). The pathogenesis of
emphysema in these patients is not known.
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Fig. 17 —44-year-old man with chronic hypersensitivity pneumonitis (farmer's
lung). High-resolution CT image shows bilateral ground-glass opacities and
centrilobular emphysema. Patient was lifelong nonsmoker. (Courtesy of Dr. Yvon
Cormier, Quebec, Canada)
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HP Not Related to Inhaled Organic Antigens
HP reaction can be seen as a manifestation of drug-induced lung disease
(Fig. 3), inhalation of
Mycobacterium avium-intracellulare complex organisms (e.g., hot tub
lung) (Fig. 18A,
18B), or exposure to
low-molecular-weight chemicals
[1,
3] (Fig.
7A,
7B,
7C). The histopathologic and
radiologic features usually are indistinguishable from those of HP secondary
to immunologic reaction to inhaled organic antigens, except for hot tub lung,
which characteristically at histologic examination has large numbers of
granulomas, sometimes necrotizing, and a relatively minor interstitial
inflammatory component.
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Fig. 18B —35-year-old man with hot tub lung. Low-power view of surgical lung
biopsy specimen shows numerous nonnecrotizing granulomas (arrows)
accompanied by chronic interstitial inflammatory infiltrate. Histologic
findings are characteristic of hot tub lung. (H and E, x40)
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Summary
A confident diagnosis of subacute HP on high-resolution CT is based on the
presence of ground-glass opacities, poorly defined centrilobular nodules, and
mosaic attenuation on inspiratory images and of air trapping on expiratory CT
images. Chronic HP is characterized on high-resolution CT by the presence of
reticulation due to fibrosis superimposed on findings of subacute HP.
Histologically subacute HP is characterized by the presence of cellular
bronchiolitis, noncaseating granulomas, and bronchiolocentric lymphocytic
interstitial pneumonitis. High-resolution CT and pathologic features of
chronic HP frequently overlap with those of NSIP and usual interstitial
pneumonia. Awareness of the various manifestations of HP is important for
early diagnosis and management to avoid progression to irreversible
fibrosis.
References
- Mohr LC. Hypersensitivity pneumonitis. Curr Opin Pulm
Med 2004; 10:401
-411[CrossRef][Medline]
- American Thoracic Society, European Respiratory Society. American
Thoracic Society/European Respiratory Society international multidisciplinary
consensus classification of the idiopathic interstitial pneumonias.
Am J Respir Crit Care Med 2002;165
: 277-304[Free Full Text]
- Travis WD, Colby TV, Koss MN, Rosado-de-Christenson ML, Müller
NL, King TE Jr. Idiopathic interstitial pneumonitis and other diffuse
parenchymal lung diseases. In: Atlas of nontumor pathology
non-neoplastic disorders of the lower respiratory tract.
Washington, DC: American Registry of Pathology and the Armed Forces Institute
of Pathology, 2002: 115-123
- Lacasse Y, Selman M, Costabel U, et al. Clinical diagnosis of
hypersensitivity pneumonitis. Am J Respir Crit Care
Med 2003; 168:952
-958[Abstract/Free Full Text]
- Vourlekis JS, Schwarz MI, Cherniack RM, et al. The effect of
pulmonary fibrosis on survival in patients with hypersensitivity pneumonitis.
Am J Med 2004;116
: 662-668[CrossRef][Medline]
- Ohtani Y, Saiki S, Kitaichi M, et al. Chronic bird fancier's lung:
histopathological and clinical correlation—an application of the 2002
ATS/ERS consensus classification of the idiopathic interstitial pneumonias.
Thorax 2005; 60:665
-671[Abstract/Free Full Text]
- Hansell DM, Wells AU, Padley SP, Müller NL. Hypersensitivity
pneumonitis: correlation of individual CT patterns with functional
abnormalities. Radiology 1996;199
: 123-128[Abstract/Free Full Text]
- Patel RA, Sellami D, Gotway MB, Golden JA, Webb WR.
Hypersensitivity pneumonitis: patterns on high-resolution CT. J
Comput Assist Tomogr 2000;24
: 965-970[CrossRef][Medline]
- Franquet T, Hansell DM, Senbanjo T, Remy-Jardin M, Müller NL.
Lung cysts in subacute hypersensitivity pneumonitis. J Comput
Assist Tomogr 2003; 27:475
-478[CrossRef][Medline]
- Cormier Y, Brown M, Worthy S, Racine G, Müller NL.
High-resolution computed tomographic characteristics in acute farmer's lung
and in its followup. Eur Respir J 2000;16
: 56-60[Abstract]
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Abstract
Introduction
