Pathology of Lung Cancer Flashcards
1
Q
What is the pathophysiology of lung cancer?
A
- A multi-step process where chronic irritation/stimulation of cells by carcinogens leads to increased cell turnover. This leads to progressive accumulation of genetic abnormalities in molecules involved in cell cycle, signalling and angiogenesis pathways
2
Q
What are the features of adenocarinoma?
A
- Make up most peripheral tumours in the lungs
- Appearance if glandular, solid, papillary or lepidic
- Also show mucin production
3
Q
What are the features of squamous carcinoma?
A
- Tend to arise centrally (around the hilus) from major bronchi
- Often have dysplastic epithelium following squamous metaplasia
- Slow growing and metastasise late
- May undergo cavitation
- May block bronchi leading to retention pneumonia or collapse
- Appearance is a malignant epithelial tumour showing keratinisation and/or intercellular bridges
4
Q
What are the features of small cell carcinoma?
A
- Make up predimonantly central tumours in the lung (around the hilus)
- Most aggressive form of lung cancer
- Metastasised early and widely
- Appearance includes oval/spindle shaped cells, inconspicuous nucleoli, scant cytoplasm and nuclear moulding
5
Q
What are the features of large cell carcinoma?
A
- Diagnosis of exclusion
- Usually arises centrally
- An undifferentiated malignant epithelial tumour that lacks the cytolofical features of SCLC and glandular or squamous differentiation
6
Q
What are the features of mesothelioma?
A
- Primary pleural tumour
- Almost always due to asbestos exposure
- Very long lag period before disease develops
- Tumour had either an epithelial or sarcomatoid appearance or a mixture of both (biphasic)
- Form lumps mass along the pleura rather than one mass
- Asbestos bodies are surrounded by macrophages which commonly take up iron as well so can be stained for iron to pick them up
- In mesothelioma cells grow up into papillae and are stratified (should only be one cell thick)
- Calretinin is a calcium binding protein that is expressed in neural cells/neurones but is also expressed in mesothelial cells (not in lung cancer)
- CK5/6 is positive in mesothelial cells but also expressed in carcinoma
7
Q
What genetic mutations are associoted with a small proportion of non-squamous lung cancers (adenocarcinoma and large cell)?
A
- EGFR
- ALK
8
Q
Histology of lung cancer
A
- NSCLC
- Squamous cell carcinoma (35%)
- Adenocarcinoma (25%)
- SCLC (20%)
- Contain neurosecretory granules that release neuroendocrine homrones
- Responsible for multiple paraneoplastic syndromes
9
Q
Signs and symptoms of lung cancer
A
- SOB
- Cough
- Haemoptysis
- Finger clubbing
- Recurrent pneumonia
- Weight loss
- Lymphadenopathy (often supraclavicular first to be found)
10
Q
Investigation of lung cancer
A
- CXR
- Hilar enlargement
- Peripheral opacity
- Pleural effusion
- Collapse
- Staging CT CAP scan
- PET-CT (shows areas of high metabolic activity suggestive of cancer)
- Bronchoscopy with endobronchial US for visualisation and bipsy
- Histological diagnosis
11
Q
Management of lung cancer
A
- MDT input
- Surgery first line in NSCLC with disease isolated to single area (i.e. lobectomy, wedge resection) or radiotherapy in NSCLC when early enough
- Chemotherapy in addition in SCLC or palliative in NSCLC
- Chemotherapy and radiotherapy in NSCLC
- Prognosis generally worse for SCLC
12
Q
Extrapulmonary manifestations
A
- Reccurent laryngeal nerve palsy (hoarse voice)
- Phrenic nerve palsy (diaphragm weakness and SOB)
- SVCO (facial swelling, difficulty breathing, distended veins in neck and upper chest, Pemberton’s sign - raising hands over head causes congestion and cyanosis)
- Horner’s syndrome (triad of ptosis, anhidrosis and miosis)
- SIADH (SCLC, presents with hyponatraemia)
- Cushing’s syndrome (SCLC)
- Hypercalcaemia (squamous cell carcinoma)
- Limbic encephalitis (SCLC, immune system makes antibodies to brain - anti-Hu antibodies, short-term memory impairment, hallucinations, confusion, seizures)
- Lambert-Eaton Myasthenic Syndrome
