T8-L2: Malignant Lung Pathology

Question 1

How can we broadly classify non-small cell carcinomas?

Answer 1

Non-small cell are responsible for 80-85% of Lung carcinomas. They can be divided into:

• Squamous cell carcinoma (20-30%)
• Adenocaricnomas (30-40%)
• Large cell undifferentiated carcinomas (10-15%)

Question 2

Which cancers commonly metastasise to the lung?

Answer 2

• Breast
• GI Tract
• Kidney
• Prostate

Sarcomas, Melanomas, Lymphomas can also metastasize from other organs and present in the lungs

Question 3

Give risk factors for lung cancer?

Answer 3

• Tobacco Smoke
• Occupation/Industrial hazards e.g. asbestos exposure
• Lung fibrosis
• Genetic mutations such as EGFR, KRAS, ALK (usually seen in non-smokers)
• Radiation

Question 4

How can smoking lead to lung cancer?

Answer 4

Tobacco smoke is an irritant. It can lead to squamous cell metaplasia, dysplasia, carcinoma in situ and then a frank carcinoma.

Question 5

Give clinical features of lung cancer.

Answer 5

Local effects - haemoptysis (due to ulceration and bleeding of a tumour), breathlessness due to obstruction and collapse and infiltrative effects (e.g. pleuritic pain, dysphagia, chest wall pain, hoarseness due to encroach on the recurrent laryngeal and sympathetic chain encroach leading to Horner’s syndrome).

Effects of distant metastasis - common sites of metastases are lymph nodes, pleura, liver, bone, adrenals, brain etc.

Non-specific effects - lethargy, weigh loss, electrolyte emplanes, finger clubbing etc.

But Lung cancer can also present asymptomatically.