Respiratory Pathology Flashcards
Roughly what percentage of deaths in England and Wales involve some respiratory pathology?
20.4%
What epithelium covers the conducting airways of the lungs?
Pseudostratified ciliated columnar mucous secreting epithelium
What is the epithelium of the alveoli?
Mostly flat type 1 pneumocytes (gas exchange) and some rounded type 2 pneumocytes (surfactant production)
What is the defines respiratory failure?
PaO2
What are the basic reasons for respiratory failure?
Due to defective:
1) Ventilation
2) Perfusion
3) Gas exchange
What is the difference between type 1 and type 2 respiratory failure?
Type 1 = paCO26.3kPa, hypercapnic respiratory drive
When does weight loss commonly occur in respiratory disease?
Catabolic state with chronic inflammation or tumours
What causes cyanosis?
Decreased oxygenation of haemoglobin
What does pleuritic pain indicate at a basic level?
Irritation of pleura
What kind of obstruction does stridor v wheeze indicate?
Stridor - proximal airway obstruction
Wheeze - distal airway obstruction
On auscultation of the lungs what abnormality do crackles indicate?
Resisted opening of airways
On auscultation what abnormality does a wheeze indicate?
Narrowed small airways
On auscultation what abnormality does bronchial breathing indicate?
Sound conduction through a solid lung
On auscultation what abnormality does pleural rub indicate?
Relative movement of inflamed visceral and parietal pleura
What does dullness on percussion indicate?
Lung consolidation or pleural effusion
What does hyperesonance on percussion indicate?
Pneumothorax or emphysema
Name 2 common lung infections?
1) Pneumonia
2) TB
Name 2 obstructive airway diseases?
1) Asthma
2) COPD
Name 3 interstitial lung diseases?
1) Adult respiratory distress syndrome
2) Fibrosing alveolitis
3) Sarcoidosis
Name 2 vascular lung diseases?
1) PE
2) Pulmonary hypertension
Name a pleural disease?
Pleural mesothelioma
Name a benign lung tumour?
Adenochondroma
What percentage of primary lung tumours are malignant carcinomas?
90%
What percentage of lung carcinomas are due to smoking?
80%
Incidence of lung cancer is second only to incidence of what cancer?
Breast cancer
The leading cause of cancer deaths in men and women in 2008 was what?
Lung cancer
What percentage of male lung carcinomas are attributable to asbestos exposure?
10%
Name 6 common risk factors for lung carcinoma?
1) Cigarettes
2) Asbestos, high level exposure with or without asbestosis
3) Lung fibrosis - including asbestosis and sarcoidosis
4) Radon
5) Chromates, nickel, tar, hematite, arsenic, mustard gas
What is asbestosis?
Pulmonary interstitial fibrosis caused by exposure to asbestos - asbestos bodies seen on light microscopy
What 4 respiratory conditions related to asbestos are prescribed occupational disease and sufferers receive industrial injuries disablement benefit?
1) Lung carcinoma with asbestosis
2) Asbestos related diffuse pleural fibrosis
3) Asbestos related silicosis
4) lung carcinoma in the absence of asbestosis if there is a history of over 5 years work in some high exposure occupations
What are carcinoid tumours?
Low grade neuroendocrine epithelial tumours
What are the 2 main classes of lung carcinomas?
1) Non small cell carcinoma
2) Small cell carcinoma
What are the 4 main types of non small cell carcinoma?
1) Squamous carcinoma
2) Adenocarcinoma
3) Large cell neuroendocrine carcinoma
4) Undifferentiated large cell carcinoma
What is common to all small cell carcinomas?
All are neuroendocrine
Are carcinomas usually exclusively small cell or non small cell?
No, multiple differentiation is common
What are more common, primary or secondary lung tumours?
Secondary tumours
What do secondary lung tumours typically look like on autopsy?
Multiple bilateral nodules, but can be solitary
What 3 things can help determine if a lung tumour is primary or secondary?
1) History - obvious if they have had a previous cancer
2) Morphology - some adenocarcinomas can be identified but not squamous
3) Antigen expression - immunocytochemistry is useful but not 100% reliable
What 2 Ag can be identified with immunocytochemistry in lung non-mucinous adenocarcinoma and small cell?
1) Cytokeratin
2) Thyroid transcription factor
What Ag can be identified with immunocytochemistry in colorectal mets?
1) Cytokeratin 20
What 2 Ags can be identified using immunocytochemistry in upper GI mets?
1) Cytokeratin 7
2) Cytokeratin 20
What Ag likely to identified using immunohistochemistry in breast mets?
Oestrogen receptor
What 3 Ags are identified using immunohistochemistry in melanoma mets?
1) S100
2) HMB45
3) MelanA
What is the typical location of lung carcinomas?
Most central, main or upper lobe bronchus (bronchogenic)
Traditionally which lung carcinoma tends to be more peripheral?
Adenocarcinoma
What are the 2 main histological features of squamous carcinoma?
1) Desmosomes link cells like epidermis
2) +/- keratinization
What is a common neoplastic syndrome associated with squamous carcinoma?
Hypercalcaemia due to parathyroid hormone related peptide
What is the basic pathological process of development of squamous carcinoma?
1) Squamous metaplasia - irritant such as smoke cause the epithelium to undergo reversible metaplastic change from pseudostratified columnar to stratified squamous type which may keratinize
2) Dysplasia - one metastatic cell undergoes irreversible genetic changes producing the first neoplastic cell
3) Developing dysplasia - neoplastic cell proliferates more successfully than metaplastic cells, the neoplastic clone replaces the metaplastic cells producing dysplasia (intra-epithelial neoplasia or carcinoma in situ)
4) Squamous carcinoma - neoplastic cells breach the basement membrane producing invasive squamous carcinoma
5) Invading neoplastic cells infiltrate lymphatic and blood vessels to produce metastases in lymph nodes and distant sites
Is squamous carcinoma more commonly central or peripheral in site?
More central
What are the main histological features of adenocarcinoma?
1) Glandular cells
2) Serous or mucous vacuoles in acinar, tubular, solid or papillary structures
Are adenocarcinomas more commonly peripheral or central?
Equally
What percentage of adenocarcinomas are found in smokers?
~80%
What percentage of squamous carcinomas are found in smokers?
~90%
What protein is expressed in many non-mucinous lung adenocarcinomas?
Thyroid transcription factor
What is bronchioalveolar carcinoma?
Spread of well differentiated mucinous or non-mucinous neoplastic cells on alveolar walls. Not invasive - adenocarcinoma in situ
What respiratory syndrome does bronchioalveolar carcinoma mimic?
Pneumonia
Is metastasis common in bronchioalveolar carcinoma?
Nodal and distal metastases are uncommon
What 3 proteins can be identified by immunocytochemistry due to neuroendocrine differentiation in lung and lung tumours?
1) Neural cell adhesion molecules
2) Neurosecretory granule proteins: chromogranin, synaptophysin
Name 4 neuroendocrine lung tumours, are all malignant?
1) Carcinoid
2) Atypical carcinoid
3) Large cell neuroendocrine carcinoma
4) Small cell carcinoma
yes but there is a spectrum of malignancy in neuroendocrine tumours
What is the growth pattern of typical carcinoid tumours?
Often grow into an occlude a bronchus
What are the histological features of carcinoid tumours? 3
1) Organoid, bland cells
2) No necrosis
3) >2 mitotic figures per 2 sqmm of a standard section
What syndrome are typical carcinoid tumours associated with?
Multiple endocrine neoplasia syndrome type 1
Are carcinoid tumours associated with smoking?
No
Are carcinoid tumours benign?
No - may invade lymphatic vessels and nodes but distant metastases to hilar nodes and distant sites are rare
There is a 95% 5 year survival
What percentage of lung carcinoids are atypical?
11%
What is the main difference between typical and atypical carcinoid tumours?
Atypical are more aggressive - metastases are common and 5 year survival reduced to 60%