Respiratory: Pathology - Diffuse interstitial disease

Question 1

Five categories of interstitial lung disease with examples

Answer 1

1. Fibrosing (e.g. idiopathic pulmonary fibrosis, associated with connective tissue diseases, radiation pneumonitis, drug reactions)
2. Granulomatous (e.g. sarcoidosis, hypersensitivity pneumonitis)
3. Eosinophilic
4. Smoking related (e.g. desquamative interstitial pneumonia)
5. Other (e.g. pulmonary alveolar proteinosis)

Question 2

Six manifestations of asbestos-related lung disease

Answer 2

1. Localised fibrous plaques (or rarely, diffuse pleural fibrosis)
2. Pleural effusions
3. Parenchymal interstitial fibrosis (“asbestosis”)
4. Lung carcinoma
5. Mesothelioma
6. Laryngeal and other extrapulmonary neoplasms (e.g. colon cancer)

Question 3

What histological findings are seen with asbestos-related lung disease?

Answer 3

Asbestos bodies (phagocytosed asbestos)
Pleural plaques (on parietal pleura)

Question 4

What is sarcoidosis?

Answer 4

Systemic disease of unknown cause characterised by noncaseating granulomas in many tissues

Question 5

In what % of sarcoidosis cases is there observable CXR changes? What are the typical changes seen?

Answer 5

Bilateral hilar lymphadenopathy or lung involvement in 90% of cases

Question 6

How is sarcoidosis diagnosed?

Answer 6

Diagnosis of exclusion histologically, only definitively confirmed by biopsy (e.g. of liver or lymph node)
Suggested by elevated IgG and Ca2+, characteristic CXR and phalangeal XR changes, and typical clinical history

Question 7

Eight symptoms of sarcoidosis. Which are the most common presenting complaint at time of diagnosis?

Answer 7

1. May be asymptomatic
2. Peripheral lymphadenopathy
3. Cutaneous lesions
4. Eye involvement
5. Hepatomegaly
6. Splenomegaly
7. Respiratory difficulties (SOB, cough, chest pain, haemoptysis)*
8. Constitutional symptoms (fever, fatigue, weight loss, anorexia, night sweats)*

• most common presenting complaint

Question 8

Describe the pathogenesis of sarcoidosis

Answer 8

Lymphocytic alveolitis with predominance of CD4+ T cells -> increased cytokine release, granuloma formation
Polyclonal hypergammaglobulinaemia
See anergy in response to common skin test Ag (e.g. Candida, Tuberculin)

Question 9

Histological changes seen in sarcoidosis

Answer 9

Noncaseating granulomas: tightly clustered epithelioid cells with Langhans or foreign body type giant cells (central necrosis unusual)
Schaumann bodies (laminated concentrations of Ca+ and protein) and asteroid bodies (stellate inclusions in giant cells) are seen in 60% of granulomas and are characteristic of sarcoidosis but can be seen in other granulomatous diseases (e.g. TB)

Question 10

Five most common organ manifestations of sarcoidosis

Answer 10

1. Lymph nodes (virtually always affected; most commonly hilar/mediastinal)
2. Lung: diffuse, scattered granulomas manifesting as reticulonodular pattern on CXR
3. Skin: discrete subcutaneous nodules, erythematous scaling plaques, mucous membrane lesions)
4. Spleen and liver
5. Eye: iritis, iridocyclitis, choroid retinitis

Question 11

What % of patients diagnosed with sarcoidosis will:
- have no or minimal residual manifestations?
- have permanent lung or ocular dysfunction?
- die (usually as a result of progressive pulmonary fibrosis and cor pulmonale)?

Answer 11

• 65-70%
• 20%
• 10-15%