Respiratory Pathology Flashcards
What is bronchiectasis?
Chronic disorder characterised by permanent dilatation of the bronchi and inflammatory changes in their walls and in adjacent lung parenchyma
Describe the pathogenesis of bronchiectasis
Recurrent inflammation of the bronchial walls combined with fibrosis in the surrounding parenchyma leads to traction on weakened walls causing irreversible dilatation
List 4 post-inflammatory causes of bronchiectasis
Allergic bronchopulmonary aspergillosis Infection (pneumonia, measles, whooping cough) Congenital (congenital hypogammaglobulinaemia, CF, immotile cilia syndrome) Reactions to inhaled toxic fumes
List 5 post-obstructive causes of bronchiectasis
Neoplasm Foreign body Inspissated mucus (in asthma) External compression (by e.g. hilar LNs, aortic aneurysm) Rarely bronchial webs or atresia
What is the most common cause of lung abscess?
Aspiration
What disease process is most often associated with lung abscess?
Bacterial pneumonia
What 3 factors are associated with aspiration?
Altered consciousness (e.g. in alcoholics)
Poor dental hygiene
Immune suppression
What bacteria are commonly found in lung abscesses?
Anaerobic
List 5 other associations of lung abscess
Pulmonary infarcts
Malignancies
Penetrating trauma
Necrotising pneumonias
Bronchial obstruction
Why does lung abscess occur mostly in the right lung?
Because the right bronchus is more vertical
List 4 important risk factors for lung cancer
Smoking
Occupational hazards
Scarring
What level of smoking places you at 20x risk of lung cancer?
>40 cigarettes/day for several years
List 5 occupational hazards which may increase risk of lung cancer
Asbestos
Crystalline silica
Radon
Polycyclic aromatic hydrocarbons
Heavy metals
Correlate the clinical presentation of lung cancers with their anatomical location
Centrally located: cough, dyspnoea, weakness
Correlate the anatomical location of lung cancers with its probable type
Distal: more often adenoma
Proximal: more often squamous or small cell
How can tissue sampling be achieved for a centrally located tumor?
Sputum
Bronchial washings/brushings
EBUS-TBNA (endobronchial U/S transbronchial needle aspirate)
Bronchial biopsy
How can tissue sampling be achieved for a peripherally located tumour?
FNA (CT-guided, ENB - electromagnetic navigation bronchoscopy-guided)
Pleural biopsy
List the 5 types of non-small cell carcinoma
Squamous cell carcinoma
Adenocarcinoma
Adenosquamous carcinoma
Large cell carcinoma
Sarcomatoid carcinoma
Does squamous cell carcinoma tend to be central or peripheral?
Central with frequent involvement of large airways
What are the histological criteria for diagnosis of a squamous cell carcinoma?
Intercellular bridges
Keratinisation
If features not obvious due to poor differentiation, immunohistochemical staining may be required
How does squamous cell carcinoma usually appear macroscopically?
Grey-white to yellow, often with a dry flaky appearance that reflects keratinisation
Necrosis and haemorrhage common, may be cavitation
What is the most common type of non-small cell carcinoma?
Adenocarcinoma
Describe the typical anatomical location of adenocarcinoma
Generally peripheral and well-circumscribed
Most unrelated to bronchi
May have pleural involvement
Describe the macroscopic appearance of adenocarcinoma
Grey-white with necrosis and haemorrhage
Mucoid appearance in tumours with extensive mucin production
Can adenocarcinoma be diagnosed on cytology? What is the advantage of this? What is the disadvantage?
Yes, usually
Cheap, low complications
However often histo is done as this gives more reliable tissue for molecular testing, which most adenocarcinomas undergo
What histological features are characteristic of adenocarcinoma?
Well to moderately differentiated tumour with glandular and/or papillary structures
Cytoplasmic mucinous vacuoles or mucin extending into stroma
What is adenocarcinoma-in-situ?
Adenocarcinoma showing growth of neoplastic cells along pre-existing alveolar structures (lepidic growth), with no evidence of stromal, vascular or pleural invasion
What is the prognosis of adenocarcinoma-in-situ/bronchiolo-alveolar carcinoma (BAC)?
Solitary BAC
Describe the typical anatomical presentation of adenocarcinoma-in-situ
Well-demarcated single or multiple nodules
“Pneumonic” pattern with involvement of whole lobe
In what clinical scenario should adenocarcinoma-in-situ be considered?
Non-resolving consolidation/pneumonia
What are the 3 histo subtypes of adenocarcinoma-in-situ, in order from most to least common?
Non-mucinous
Mucinous
Mixed mucinous and non-mucinous
What line of differentiation does small cell carcinoma show?
Neuroendocrine
List 8 complications of lung cancer
Lipid pneumonia distal to obstructing tumour (due to build-up of surfactant)
Atelectasis
Bronchitis
Bronchiectasis
Cavitation and abscess formation
Fistula formation
Pleuritis, pleural effusion
Vascular thrombosis
What are the 4 most common sites of distal metastases for lung cancer (from most to least common)?
Adrenals
Liver
Brain
Bone
What are the 4 most common types of cancer metastasising to the lungs?
Breast
Lower GIT
Melanoma
RCC
Describe the typical anatomical presentation of small cell carcinoma
Rapidly growing mass often with local obstruction (e.g. major bronchi, SVC)
Often regional LN or distant metastases at initial presentation
