Lungs

Question 1

Define pneumoconiosis.

Answer 1

Pneumoconiosis is defined as the non neoplastic lung reaction to inhalation of mineral dusts or chemical fumes and vapors.

Eg. Coal workers pneumoconiosis, Silicosis, Asbestosis

Question 2

What are pleural plaques?

Answer 2

They are most common manifestation of asbestos exposure.

Gross: Pearly white; well- circumscribed plaques (may be over 10 cm in diameter).

Location:

• Usually bilateral
• Seen on anterior and posterolateral aspects of parietal pleura and domes of diaphragm

Microscopy:

• Acellular, dense fibrous tissue, with slit-like spaces
• arranged in a parallel fashion (basket-weave pattern)
• Often calcified
• Do not contain asbestos bodies

Question 3

Asbestosis— Definition, Pathogenesis, Morphology.

Answer 3

Asbestosis is defined as interstitial fibrosis of the lung caused by exposure to asbestos dust.

Caused by Asbestos inhalation (shipping industry/battery industry)
2 types of asbestos:
1. Crystalline form (flexible, more soluble)
2. Amphibole form (more rigid, less soluble)- More pathogenic

Pathogenesis:
Inhaled— reach alveolar spaces— engulfed by macrophages — release inflammatory mediators and FIBROGENIC MEDIATORS
Chronic exposure — persistent release of fibrogenic mediators— generalised interstitial inflammation and fibrosis.

Morphology:

1. Gross: Begins in lower lobes
2. Microscopy: Diffuse interstitial fibrosis, Asbestos bodies, Ferruginous bodies.

Asbestos bodies: Spindle shaped rodlike fibres coated with iron.

Question 4

Define pneumonia.

Answer 4

Pneumonia is defined as infection of the lung parenchyma. It causes the alveoli to be filled with
inflammatory exudates and usually results in consolidation (solidification) of lung.

• Lowered systemic resistance of the host: It may be due to
– Chronic diseases.
– Immunological deficiency
– immunosuppressive drugs

• Impaired local defense mechanisms
– Loss or suppression of the cough reflex

– Damage or injury to the mucociliary apparatus

– Accumulation of secretions

– Interference with the phagocytic or bactericidal action of alveolar macrophages:

– Pulmonary congestion and edema

Question 5

Morphology of asbestosis.

Answer 5

Gross:

1. In early stages, interstitial fibrosis may not be apparent
2. Later there is generalized fibrosis of the lungs and disruption of architecture

Microscopy:
1. Asbestos bodies: Formed by the asbestos fibres in the alveoli. They have a translucent centre, covered with proteins rich in iron. They are thickened at the poles- dumbbell shaped

2. Ferruginous bodies: Other particulate matters coated wjth proteins rich in iron
3. Diffuse pulmonary intestitial fibrosis

Question 6

Morphology of coal workers pneumoconiosis.

Answer 6

Parenchymal lung disease caused by inhalation of carbon dust.

Morphology: 3 stages:-
1) Asymptomatic anthracosis: Harmless lesions consisting of carbon laden macrophages

2) Simple coal worker’s pneumoconiosis
Gross: Coal macules, Coal nodules
HPE: Macules- Macrophages with carbon, Nodules- Carbon laden macro+ collagen deposits

3) Complicated coal workers pneumoconiosis
- Progressive massive fibrosis
- Large black scars containing carbon and collagen with necrotic centre

Question 7

Asteroid bodies are seen in which disease —?

Answer 7

Sarcoidosis

Question 8

What is sarcoidosis?

Answer 8

It is a granulomatous disease, involving various tissues, characterized by formation of granulomas.

• Type 4 hypersensitivity reaction.
• HLA A1 and HLA B8 associated.

Most commonly affected are: Lungs and hilar lymph nodes, skin, eye.

HPE:

1) Non caseating and naked granulomas
2) Asteroid bodies
3) Schaumann bodies