Malignant lung pathology

Question 1

Common sites of lung metastasis =

Answer 1

bones, brain, lymph nodes

Question 2

Most common primary malignant lung tumour =

Answer 2

Carcinomas (>90%) – adenocarcinoma most common subgroup

Question 3

Small cell carcinoma definition

Answer 3

• Less cytoplasm
• Fine nuclear chromatin
• Less prominent/no nucleoli

Question 4

Non-small cell carcinoma

Answer 4

• Usually more cytoplasm
• Clumped/vesicular nuclei
• More prominent nucleoli

Question 5

Types of non-small cell carcinoma

Answer 5

• Squamous cell carcinoma - Show keratinisation and dark nuclei
• Adenocarcinoma - most common - Lots of cytoplasm + glandular structures
• Large cell undifferentiated carcinoma = Show no keratinisation or gland formation

Question 6

Other primary malignant lung tumours

Answer 6

• Carcinoid tumours = rarer tumours but low grade so better prognosis
• Malignant mesenchymal tumours = very rare, most common type = synovial sarcoma
• Primary lung lymphomas = rare - often seen in HIV/AIDS patients

Question 7

Secondary lung tumours

Answer 7

• Very common, more common than primary tumours as almost all tumours in body can metastasise to lungs
• Usually present as multiple discrete nodules but can also be solitary (rare)
• Most common are carcinomas from any part of the body

Question 8

Epidemiology of lung cancer

Answer 8

• Most common cause of cancer death
• M>F only slightly
• 40-70 years

Question 9

Aetiology of lung cancer

Answer 9

• Smoking
• Asbestos - Latent period around 20 years between exposure and development
• pulmonary fibrosis increases risk, genetic mutations, radiation

Question 10

Pathogenesis of lung cancer

Answer 10

• Mutations in key genes regulating cell proliferation, DNA repair and apoptosis

Question 11

Local effects of lung cancer

Answer 11

• Bleeding = haemoptysis
• Obstruction of airways
• Infiltration of pleura, ribs, oesophagus
• Horner’s syndrome
• Recurrent laryngeal nerve = hoarseness

Question 12

Distant metastases of lung cancer

Answer 12

• Common sites: lymph nodes, pleura, liver, bone, adrenal, brain
• Lymphangitis carcinomatosa = infiltration of lymphatic vessels by the cancer cells
• Depending on the site can present with pathological fractures, seizures, lumps in necks

Question 13

Non-specific features of lung cancer

Answer 13

• Usually metabolic effects = weight loss, lethargy, finger clubbing
• Electrolytic disturbances e.g. small cell carcinoma = hyponatraemia, hypokalaemia, hypercalcaemia in SCC

Question 14

Management of primary lung cancer

Answer 14

• If not metastasised - Surgery or radical radiotherapy

- Advanced disease = chemotherapy and palliative radiotherapy