Emphysema is an obstructive lung disease characterized by permanent enlargement of the air spaces distal to the terminal bronchioles without significant fibrosis. There are three main types: centriacinar, panacinar, and paraseptal emphysema. The predominant symptoms are dyspnea and cough. Emphysema is usually caused by cigarette smoking and air pollution and presents in older adults. Treatment focuses on smoking cessation, medications, oxygen therapy, surgery, and replacement therapies. The main causes of death relate to respiratory failure and heart disease.

1. FLASHPATH
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2. EMPHYSEMA
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3. CLINICAL
Emphysema is one of the “obstructive lung diseases” that include:
• Chronic bronchitis
• Bronchiectasis
• Small-airway disease “bronchiolitis”
• Asthma

4. CLINICAL
Obstructive airway disease Restrictive airway disease
General features Increase in resistance to
airflow due to obstruction at
any level
Reduced expansion of lung
parenchyma
Total lung capacity (TLC) Increased Reduced
Forced Expiratory Volume in
one second (FEV1)
Reduced Normal

5. CLINICAL
• Emphysema and chronic bronchitis are often clinically grouped together
and referred to as chronic obstructive pulmonary disease (COPD)
• COPD is the 3rd leading cause of global death
• Usually due to cigarette smoking and air pollution
• Usually present in adults (> 45 years old) and more common in males
• Main symptom are dyspnea and cough

6. CLINICAL
Predominant Chronic Bronchitis Predominant Emphysema
Age 40 – 45 years old 50 – 75 years old
Appearance Blue Bloater Pink Buffer
Dyspnea Mild, Late Early, Severe
Cough Early
Copious sputum
Late
Scanty sputum
Infections Common Occasional
Respiratory Insufficiency Repeated Terminal
Cor pulmonale Common Rare, Terminal
Radiology Prominent vessels
Large heart
Hyperinflation
Small heart
Airway Resistance Increased Normal or slightly increased
Elastic Recoil Normal Low

7. CLINICAL
• Emphysema is:
– Permanent enlargement of air spaces
– Distal to the terminal bronchioles (= Acini)
– Due to destruction of the alveolar septa
– Without fibrosis
• Three main types:
Centriacinar Panacinar Paraseptal
% 97% 1% 2%
Affected
segment
Proximal parts of acini
“Respiratory bronchioles = RB”
Entire acini
“RB + alveolar duct + alveoli”
Distal parts of acini
“near septa/pleura”
Lobe Mainly upper lobes Mainly lower lobes Mainly sub-pleura
Cause Smoking α1-antitrypsin deficiency Fibrosis, atelectasis

8. CLINICAL
• Centriacinar emphysema can be seen also in coal workers
pneumoconiosis
• Panacinar emphysema can be seen also in talc IV drug abuse
and in Ritalin use

9. CLINICAL
Lines of treatment:
• Smoking cessation
• Medications (Bronchodilators, Steroids)
• Oxygen therapy and Ventilatory support
• Surgical (Lung volume reduction surgery, Lung transplant)
• Replacement therapy (for alpha-1-antitrypsin deficiency)
Main causes of death:
• Coronary artery disease
• Respiratory failure
• Right-sided heart failure
• Massive lung collapse “secondary to pneumothorax”

10. PATHOGENESIS
• Inflammatory mediators
– Smoking  stimulate inflammation & inflammatory mediators
• Protease / antiprotease imbalance ( = loss of elastin)
– Smoking  increases elastase “protease”
• released from neutrophils
– Smoking  decrease of protective antiproteases
– Alpha – 1 antitrypsin deficiency  deficiency of antiproteases
• Oxidative stress
– Oxidants are released by smoke substance, damaged tissue, and inflammatory
cells  more tissue damage
• Genetic predisposition
– Some people are genetically more susceptible to these factors than others

11. GROSS
• Increased weight and size of lungs
– Overlap “hide” the heart in situ
• Outer surface
– Blebs (< 1 cm) or bullae (> 1 cm)
may be seen
• Cut section
– Large, cystic alveoli
– Anthracosis
• especially in centriacinar type

12. GROSS
• Centriacinar type:
Both emphysematous (E) and normal airspaces
exist within the same acinus and lobule
• Panacinar type:
All airspaces within acini are evenly enlarged
• Paraseptal type:
Subpleural airspaces is mainly affected

13. MICROSCOPY

14. MICROSCOPY
Histological landmarks of lung acinus:
• Bronchovascular bundle “terminal bronchiole and arteriole”
– In the center of acinus
• Connective tissue septa "secondary lobule of Millar"
– At the periphery of acinus
– Often ambiguous in less inflamed lung
• Helpful to determine emphysema types
– Upper pic  Centriacinar
– Lower pic  Panacinar

15. MICROSCOPY
Emphysema is characterized by:
• Abnormal enlargement of airspaces
• “Floating” alveolar walls fragments within enlarged airspace
• No or little fibrosis
• Any degrees of chronic inflammation
The pores of Kohn are so large that septa
appear to be floating or protrude blindly
into alveolar spaces with a clubshaped end

16. MICROSCOPY
• Other Smoking-related conditions:
– Anthracosis
– Desquamative interstitial pneumonia
– Small airway disease
• Respiratory bronchiolitis
• Respiratory bronchiolitis-associated interstitial lung disease
– Large airway disease
• Chronic bronchitis
– Pulmonary eosinophilic granuloma
• “Langerhans cell histiocytosis”
– Interstitial fibrosis
• Pulmonary hypertension

17. DIFFERENTIAL DIAGNOSIS
Other types of emphysema:
• Combined pulmonary fibrosis and emphysema (CPFE)
– Coexistence of interstitial fibrosis and emphysema of unknown causes
– Poor prognosis in comparison to pure emphysema or pure lung fibrosis
• Interstitial emphysema
– Air gains access to the pulmonary interstitium to cause air leak and
pneumothorax
– Common in premature infants
• Bullous emphysema
– Formation of multiple bullae > 1 cm with thin wall to cause pneumothorax

18. DIFFERENTIAL DIAGNOSIS
Other types of emphysema:
• Senile emphysema
– Due to age related alteration of acini
• Irregular emphysema
– Occurs in relation to scars
• Congenital lobar emphysema
– Hyperinflation of one or more lobes due to malformation of bronchioles
– Causes respiratory distress

19. DIFFERENTIAL DIAGNOSIS
Chronic
bronchitis
Bronchiectasis Asthma
Small-airway
disease
“bronchiolitis”
Emphysema
Site B r o n c h u s Bronchioles Alveoli
Major
pathology
• Mucous gland
hyperplasia
• Excess mucus
• Inflammation
• Airway
dilation &
scarring
• Smooth
muscle
hyperplasia
• Excess mucus
• Inflammation
(eosinophils)
• Inflammatory
scarring &
obliteration
• Airspace
enlargement
• Wall
destruction
• No fibrosis
Other obstructive lung diseases:

20. DIFFERENTIAL DIAGNOSIS
O t h e r c o n g e n i t a l / c y s t i c l u n g d i s e a s e s :
• Congenital:
– Bronchogenic cysts
– Congenital pulmonary cysts
– Congenital pulmonary airway malformation
– Congenital lobar emphysema
– Pulmonary sequestration
• Acquired:
– Healed abscess
– Honeycombing
• Mixed:
– Cystic fibrosis
No destruction of alveoli
Fibrosis

21. DIFFERENTIAL DIAGNOSIS
Autolysis and inadequate fixation
• Similar gross and microscopic appearance can be seen due to
inadequate inflation or fixation of the specimen with formalin
– Clinical history
– Other smoking-associated conditions
Favor emphysema

22. DIFFERENTIAL DIAGNOSIS
Lymphangioleiomyomatosis Vs Emphysema?
• Women of reproductive age
• Multiple cysts and blebs of the lung
– Mural thickening around some cystic spaces
– Chylous pleural effusion
• Interstitial proliferation of smooth muscle-like cells around airways and
blood vessels
– Tumor cells are positive for HMB45
• Other Tuberous Sclerosis-Associated lesions (e.g. PEComas)

23. DIFFERENTIAL DIAGNOSIS
Placental transmogrification of the lung
• Very rare disease
• Mainly seen in middle-aged males
• Historically considered a microscopic variant
of emphysema
• Solitary giant bullous
– With/without solid nodules
• Papillary/villous structures resembling chorionic villi within cystic space
– Villi cores contain fat cells and primitive mesenchymal clear cells
• Can be associated with pulmonary fibrochondromatous hamartomas

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