Lecture 16

Question 1

What is the general pathogenesis of lung cancer?

Answer 1

• Progressive transformartion of benign bronchial epithelium into neoplasm due to mutations such as 3p deletions, p53 mutations, K-ras mutations
• 90% associated with smoking

Question 2

What are the main types of primary lung cancer?

Answer 2

• Small cell lung cancer (20-25%)
• Non-small cell lung cancer (70-75%)
  
  • Squamous
  • Adenocarcinoma
• Combined (5-10%)

Question 3

What are small cell lung cancers often due to and how does this relate to treatment?

Answer 3

• Often due to EGFR mutations which causes over stimulation of tyrosine kinase receptors
• 2 drugs have been developed that inhibit TK
  
  • Erlotinib
  • Gefitinib

Question 4

What are the clinopathological features of lung cancer 1?

Answer 4

• Local effects - cough, dyspnoea, obstructve pneumonia
• Local spread - pleural effusions, nerve entrapment (e.g horners syndrome which is when an optic nerve fucks out)
• Mediastinal spreas - SVC obstruction, nerve entrapment (e.g nerve to vocal cords fucking out –> hoarse voice)

Question 5

Where are the common spreads of primary lung cancer?

Answer 5

• Metatstartic spread:
  
  • regional lymph nodes
  • extranodal e.g brain, bone, liver and adrenal

Question 6

What are the paraneoplastic syndromes that arise from lung cancer?

Answer 6

• Small cell lung cancer can –> Cushing syndrome secondary to ACTH; Inappropriate ADH secretion (would lead to low sodium)
• Non-small cell cancer can –> hypercalcaemia secondary to PTH-rp
• Finger clubbing (not specific to lung cancer)

Question 7

What are the features of squamous cell carcinomas of the lung?

Answer 7

• 30% of all lung cancer
• Strong link with smoking
  
  • Injury to bronchial epithelium
  • Sequence of dysplasia, carcinoma in situ, invasive tumour
• Most arise centrally in major or segmental bronchi
• Pathology:
  
  • Firm, grey, ulcerated lesions in bronchial wall
  • Extend through into adjacent lung parenchyma
  • Often show necrosis, cavitation
  • Microscopy shows variable differentiation, with keratin pearls, intercellular bridging

Question 8

What are the features of adenocarcinomas of the lung?

Answer 8

• 30% of invasive lung cancers
• Most common type seen in non smoker
• Peripheries of lungs
• Present with chest pain, pnemonia, horners syndrome

Question 9

What are the features of bronchialveolar carcinomas?

Answer 9

• Subtype of adenocarcinoma arising existing alveolar walls
• Up to 5% of all lung cancers

Question 10

What are the features of small cell carcionmas of the lung?

Answer 10

• 20% of invasive lung cancers
• Strong link with smoking
• Often associated with Paraneoplastic syndromes]
• Highly malignant, epithelial tumour but exhibits neuroendocrine features
• Arise as peri-hilar mass, often with lymph node invasion
• Frequently shows haemorrhage and necrosis on cut section
• Microscopically sheets of small round or spindle shaped cells, high mitotic rate

Question 11

What are the other lung cancers?

Answer 11

• Large cell carcinomas (5%)
• Carcinoid tummour (neuroendocrine)
• Pulmonary metastatic disease most common cause of neoplasm of the lung

Question 12

What are the tumours of the pleura?

Answer 12

• Malignant mesothelioma
  
  • asbestos fibre exposure