Pathology of pleura, pleural spaces

Question 1

what is pleural effusion

Answer 1

Accumulation of fluid in the pleural space (normal <15ml);
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Manifestation of both primary and secondary pleural diseases

Question 2

Pleural effusion is due to what?

Answer 2

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increased hydrostatic pressure (e.g. congestive heart failure),
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increased vascular permeability (e.g. pneumonia),
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decreased osmotic pressure (e.g. nephrotic syndrome),
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increased intrapleural negative pressure (e.g. atelectasis) or
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decreased lymphatic drainage (e.g. mediastinal carcinomatosis)

Question 3

explain the serous, serofibrinous and fibrinous pleuritis

Answer 3

• Serous, serofibrinous and fibrinous pleuritis:
  Aetiology :usually due to inflammation of the underlying lung
  o
  Tuberculosis, pneumonia, lung infarction
  o
  Systemic conditions e.g. Rheumatoid arthritis, uraemia, metastatic pleural involvement, radiotherapy for lung/pleural tumours
  o Usually resolves with resorption of fluid +/- organisation of the fibrinous component

Question 4

explain the haemorrhagic pleuritis

Answer 4

Sanguineous( resemblingor containing blood).
inflammatory exudate (different from haemothorax); Hemorrhagic pleural effusion is defined as an erythrocyte count greater than 100,000 cells/μl.2
uncommon and tumour involvement of the pleura must be excluded

Question 5

explain the serous pleural effusion gross

Answer 5

This is fluid collection into a body cavity—an effusion. This is a right pleural effusion (in an infant). Note the clear reflective, pale yellow appearance of the fluid, indicative of a serous effusion.

Question 6

explain the empyema (purulent pleural exudate)
Gross
Volume
Causes

Answer 6

Gross- Empyema, gross
This pleural surface has an overlying thick, yellow-tan purulent exudate. Adjacent unaffected lung with dark anthracotic pigment at the far right..
Causes: due to bacterial or mycotic seeding of the pleural space (e.g. spread from intrapulmonary infections or more distant sources)
o Volume is usually small and the pus gets walled off by fibrosis; usually organizes into dense, tough fibrous adhesions that obliterate the pleural space or encases the lung (empyema peel) and can restrict lung expansion

Question 7

list 3 non-inflammatory effusions

Answer 7

Hydrithorax (serous fluid)
Haemothorax (blood)
Chylothorax (lymph fluid)

Question 8

Milky white appearance due to finely emulsified fats. Usually due to thoracic duct trauma or obstruction of a major lymphatic duct (usually by malignancy)

Answer 8

Chylothorax (lymph fluid)

Question 9

Most commonly due to heart failure; also seen in other systemic
conditions associated with generalized oedema e.g. renal failure, liver cirrhosis

Answer 9

Hydrothorax (serous fluid)

Question 10

is a pleural fluid with blood hematocrit ratio greater than 50% . Compare to haemorrhagic effusion .Usually due to trauma, surgery or rupture of aortic aneurysm

Answer 10

Hemothorax (blood)

Question 11

what is haematocrit

Answer 11

Haematocrit: /ˈthe ratio of the volume of red blood cells to the total volume of blood.

Question 12

You compare which non-inflammatory effusions

Answer 12

Haemorrhagic to haemothorax

Question 13

Explain pneumothorax and list 3 examples

Answer 13

• Air/gas in pleural cavity, usually associated with emphysema, asthma or tuberculosis
  Spontaneous pneumothorax
  Traumatic pneumothorax
  Tension pneumothorax

Question 14

Usually due to perforating injury to chest wall

Answer 14

Traumatic pneumothorax

Question 15

When a pleural defect acts as an air valve allowing air entry during
inspiration but does not allow air escape during expiration, resulting in progressively increasing
intrapleural pressure that can compress and cause deviation of vital mediastinal structures away
and compress the contralateral lung

Answer 15

Tension pneumothorax

Question 16

As a complication of any pulmonary disease that causes
emphysematous change, a communicating abscess cavity, or idiopathic (usually in young people due
to rupture of small, peripheral usually apical, subpleural blebs)

Answer 16

Spotaneous pneumothorax

Question 17

what is pleural tumours

Answer 17

Secondary involvement of the pleura by metastases is more common than primary pleural tumours,
usually from lung or breast primary tumours and often producing a serous or serosanguineous pleural
effusion

Question 18

where does the malignant mesotheliom arises

Answer 18

Malignant tumour arising from mesothelial cells lining the serous cavities

Question 19

what are the risk of malignant mesothelioma

Answer 19

Risk factors: Asbestos exposure (long latent period; risk is not magnified by smoking, unlike
asbestos-related lung carcinomas)

Question 20

explain the clinical findins of malignant mesothelioma

Answer 20

Clinical findings: Presents with chest pain, dyspnoea, recurrent pleural effusions. Generally poor
prognosis

Question 21

explain the gross of malignant mesothelioma

Answer 21

• Gross: Diffuse soft greyish-pink tumour arising from either visceral or parietal pleura; usually
  associated with extensive pleural effusion and direct invasion of thoracic structures

Question 22

explain the microscopic appearance of malignant mesothelioma

Answer 22

• Microscopy: Epithelioid (60-80%), sarcomatoid (10%) or biphasic (10-15%) morphology

Question 23

explain the picture of malignant mesothelioma

Answer 23

Malignant mesothelioma, gross
The dense, white encircling tumor mass () arising from the visceral pleura is a malignant mesothelioma.
These are big, bulky tumors that can fill the chest cavity.
The risk factor for mesothelioma is prior asbestos exposure.
Asbestosis more commonly predisposes to bronchogenic carcinomas, increasing the risk by a factor of five.
Smoking increases the risk for lung cancer by a factor of 10.
Smokers with a history of asbestos exposure have a 50-fold greater likelihood of developing bronchogenic lung cancer

Question 24

picture of maligant mesothelioma microscopic appearance

Answer 24

Malignant mesothelioma, microscopic
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There are either spindle cells or plump, rounded cells forming glandlike configurations (▲) as shown here in the pleura.
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Cytogenetic abnormalities are often present, as arep16andTP53mutations.
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Rare, even in individuals with asbestos exposure, and are virtually never seen in individuals without a history of asbestos exposure.
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In addition to the pleura, other, less common sites of occurrence of this neoplasm are the peritoneum, pericardium, and testicular tunica.