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32 Pleural diseases.pptx
1. DISEASES OF THE PLEURA
DR O.O ODUJOKO
DEPT. OF MORBID ANATOMY AND
FORENSIC MEDICINE, OBAFEMI
AWOLOWO UNIVERSITY, ILE-IFE.
2. • Normally the pleural cavity contains about
15mls of clear, serous acellular fluid which
lubricates the pleural surface.
• Accumulation of pleural fluid is known as
pleural effusion and it occurs in the following
settings
3. • Increased hydrostatic pressure as in congestive
cardiac failure
• Increased vascular permeability as in pneumonia.
• Decreased osmotic pressure as in nephrotic
syndrome
• Increased intrapleural negative pressure as in
atelectasis
• Decreased lymphatic drainage as in mediastinal
carcinomatosis
4. Inflammatory pleural effusions
• This could be serous, serofibrinous and
fibrinous pleuritis
• Common causes include disorders associated
with inflammation of the underlying lung such
as tuberculosis, pneumonia, lung infarcts, lung
abscess.
• Other causes are systemic lupus
erythematosus, rheumatoid arthritis, uremia
as well as metastatis to the pleura.
5. • Radiation used to treat tumours can also cause
pleuritis with pleural effusion
• If the pleural effusion is made up of a purulent
exudate, it is called empyema.
• Empyema is usually a result of infection by
bacteria or fungal organisms
• The seeding of the pleura is commonly a
contigous spread from the lungs but may also
occur as a result of spread from a distant site
through the lymphatics or blood.
6. • The infection may also be as a result of spread
from below the diaphragm as in liver abscess.
• The volume of accumulated fluid in empyema
is usually small although it could occasionally
reach 500-1000mls
• It usually resolves but more often, it usually
gets organized into a tough fibrous adhesion.
• This may restrict lung expansion
7. • Haemorrhagic pleuritis is infrequent and it
may complicate rickettsial infection or
neoplastic involvement of the pleural cavity.
• It may also be seen in haemorrhagic diathesis.
• In cases of haemorrhagic pleuritis, careful
search should be made for presence of
exfoliated malignant cells.
8. Non-inflammatory effusions
• Non-inflammatory collections of pleural fluid
within the pleural cavities are called
hydrothorax.
• It may be unilateral or bilateral. It is usually
unilateral in Meig’s syndrome
• The most common cause is cardiac failure.
• Other causes are renal failure and liver
cirrhosis
9. • Presence of blood within the pleural cavity is
known as haemothorax
• It can be as a result of ruptured aortic
aneurysm
• Vascular trauma may also be a cause
• Chylothorax is usually the presence of milky
fluid usually lymph in the pleural cavity. It can
result from damage to the thoracic duct or
obstruction within the lymphatic vessels
10. Pneumothorax
• This refers to the presence of air or gas within the
pleural cavity
• It is most commonly due to emphysema, asthma
and tuberculosis.
• Pneumothorax can be due to a penetrating injury
into the chest wall allowing air into the pleural
cavity
• If the injury penetrates into the lung substance,
air may also gain access to the pleural cavity from
the alveolar spaces.
11. • There is also a spontaneous idiopathic
pneumothorax.
• This entity is seen in young, slim and tall
individuals
• It seems to be due to rupture of small, peripheral
apical subpleural blebs.
• It subsides spontaneously but it may recur.
• Pneumothorax may cause compression of the
lungs with consequent respiratory distress and
atelectasis.
12. PLEURAL TUMOURS
• Tumours within the pleura may be primary or
secondary.
• Secondary tumours are far commoner and
they may be from the lungs, breast, ovaries
and other organs.
13. Solitary fibrous tumour
• Also called a benign mesothelioma
• It occurs in the pleura, lungs.
• It usually remains confined to the lungs
• Grossly it contains dense fibrous tissue with
occasional cysts filled with viscid fluid
14. Malignant mesothelioma
• It is a rare tumour
• Exposure to asbestos is a strong risk factor
• It arises from either the parietal or visceral
pleura.
• The lifetime risk of developing this tumour in
those who are exposed to asbestos is 7-10%
• The latent period for the development is
between 25-45 years.
15. • The risk of mesothelioma is not increased in
those who are exposed to abestos and also
cigarette smoke
• This is in contrast to the risk of lung cancer
development in those who are exposed to
asbestos and cigarette smoke.
• Asbestos bodies are found in increased
numbers in the lungs of patients with
mesothelioma
16. • The most common cytogenetic alteration in
mesothelioma is homozygous deletion of the
CDKN2A gene.
• It occurs in 80% of the tumours
• It is sometimes helpful in distinguishing
reactive mesothelial proliferations from
malignant mesothelioma.
17. MORPHOLOGY
• Malignant mesothelioma arises from the
pleura and spraeds widely in the pleural
space.
• It is usually associated with extensive pleural
effusion
• It invades directly many structures within the
thoracic cavity.
• It appears as a greyish-pink gelatinous tumour
that ensheathes the lungs
19. • Microscopically, malignant mesotheliomas
may be epitheloid (60%), sarcomatoid (20%)
or mixed (20%)
• This is because normal mesothelial cells can
differentiate towards epithelial-like cells or
mesenchymal cells.
• The epitheloid type are cuboidal or columnar
and form tubular and papillary patterns thus
mimicking adenocarcinomas.
21. • Clinical features include chest pain, dyspnea, as
well as recurrent pleural effusion.
• The lung may be invaded by the tumour
• Metastasis occurs to hilar lymph nodes and
eventually to the liver and distant organs.
• About 50% of the patients die within two years
• Mesotheliomas can also arise from the peritoneal
cavity, pericardial cavity, tunica vaginalis and
genital tract.
