Emphysema
Epidemiology:
- Heavy smokers à centriacinar
emphysema
Common sites:
Gross features:
- centriacinar:
- upper lobes,
particularly apical segments are more involved
- black pigment in
the walls of emphysematous spaces
- less impressive enlargement
than panacinar
- panacinar:
- Bases most
severe
- lower zones and
anterior margins more affected
- voluminous lungs
often overlapping over the heart
- Distal acinar (paraseptal):
- More severe in
upper half of lungs
- Large apical
blebs or bullae
- Adjacent to
pleura and along lobular connective tissue septa, and margins of lobules
- Adjacent to
areas of fibrosis, scarring, or atelectasis
- Airspace
enlargement with fibrosis (irregular emphysema):
- Associated with
areas of scarring
Histologic features:
- Abnormally large
alveoli
- Thin septa with
only focal centriacinar fibrosis
- Loss of
attachments of alveoli to outer wall of small airways
- Enlarged pores of
Kohn – septa appear to be floating
- Respiratory
bronchioles and vasculature become deformed and compressed in advanced
stages
- Chronic bronchitis
or bronchiolitis
- centriacinar (centrilobular):
- central or
proximal parts of acini (respiratory
bronchioles) affected, whereas distal alveoli are spared
- inflammation
around bronchi and bronchioles
- panacinar (panlobar):
- acini uniformly enlarged from respiratory
bronchiole to terminal blind alveoli
- distal acinar (paraseptal)
emphysema:
- proximal protion of the acinus is
normal, and distal part is predominantly involved
- airspace
enlargement with fibrosis (irregular emphysema):
- acinus is irregularly involved
- you may see:
- hypersensitivity
pneumonitis (inhalers)
- fibrosis around
blebs and bullae
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
- abnormal permanent
enlargement of airspaces distal to the terminal bronchiole
- no obvious
fibrosis
- centriacinar (centrilobular) is most
common (>95%)
- panacinar (panlobular)
is associated with alpha-1-antitrypsin deficiency
- distal acinar (paraseptal) may underly many cases of spontaneous pneumothorax
in young adults
- airspace
enlargement with fibrosis (irregular emphysema):
References: