Respiratory tract: neoplastic disease

Question 1

Lung tumours

Answer 1

Benign and malignant tumors may arise in lung
Vast majority (90% to 95%) are carcinomas (arising from lining epithelium)
About 5% are bronchial carcinoids (neuroendocrine)
2% to 5% are mesenchymal and other miscellaneous neoplasms including sarcomas and lymphomas

Question 2

Lung carcinomas

Answer 2

2nd most common cancer in UK
Incidence increasing in females, decreasing in males
Age 40-70 years
Male > female
5 year survival 8% (men), 9% (women)

Question 3

lung tumours risk factors

Answer 3

Smoking
Industrial hazards
Family history
Immunodeficiency

Question 4

smoking and lung tumours

Answer 4

Statistical evidence
87% of lung carcinoma in active smokers/recently stopped smoking
3000 non smokers die of lung ca/year – passive smoking
Linear correlation between exposure to cigarette smoke and epithelial changes (metaplasia, dysplasia, CIS, invasive carcinoma)
Also associated with carcinoma of the mouth, pharynx, larynx, oesophagus, pancreas, cervix, kidney and bladder

Question 5

Clinical details of Lung tumours

Answer 5

Presenting complaint
Cough (75%)
Weight loss (40%)
Chest pain (40%)
Dyspnoea (20%)
May present with symptoms of metastases
Local extension of tumour within pleural cavity, to pericardium
Spread to tracheal, bronchial and mediastinal nodes found in most cases; nodal involvement average >50%
Most common distant spread adrenals (>50%), liver (30-50%), brain (20%), bone (20%)

Question 6

Paraneoplastic syndromes

Answer 6

Ectopic hormone secretion by tumour
Incidence 1-10% of all lung cancer patients
Hormones involved include:
Antidiuretic hormone (ADH) – hyponatraemia
Adrenocorticotrophic hormone (ACTH) – Cushing syndrome
Parathormone, parathyroid hormone-related peptide, prostaglandin E, cytokines – hypercalcaemia
Calcitonin – hypocalcaemia
Gonadotropins – gynaecomastia
Serotonin and bradykinin – carcinoid syndrome

Question 7

Lung Carcinoma – Staging - TNM

Answer 7

‘T’ - Primary tumour size/degree of invasion?

‘N’ – Lymph nodes positive or not ?

‘M’ – Distant metastases or not ?

Question 8

Small cell carcinoma

Answer 8

Strong relationship to smoking – 1% occur in non smokers
Occur in major bronchi and at periphery
Rapidly invade bronchial wall and parenchyma; early lymphatic and blood-borne spread
Therefore mostly incurable by surgery
Most responsive to chemotherapy – but worst prognosis as relapses early

HISTOPATHOLOGY: small, tightly packed, darkly stained ovoid tumour cells (resemble oats – also termed oat cell carcinoma)

Question 9

Squamous cell carcinoma

Answer 9

Most commonly affects men
Closely correlated with smoking history
Arises close to hilum, usually in area of squamous metaplasia (due to cigarette smoke)

HISTOPATHOLOGY: well differentiatied resembles stratified squamous epithelium; characterised by keratin formation and/or intercellular bridges
90% of cases are smokers

Question 10

Adenocarcinoma

Answer 10

Most common type in women and non-smokers (but >75% found in smokers)
Tend to be peripherally located
Grow more slowly than SCC but metastasize early and widely
Sometimes associated with scarring e.g. healed TB

HISTOPATHOLOGY: well differentiated have obvious glandular elements; 80% contain mucin

Question 11

Large cell carcinoma

Answer 11

Undifferentiated malignant epithelial tumour
Undifferentiated SCC and adenocarcinoma with no discernible features by light microscopy
HISTOPATHOLOGY: large, anaplastic epithelial cells growing in islands and sheets
Neuroendocrine variant – highly malignant; nests and islands of tumour cells with granular cytoplasm, central necrosis, peripheral palisading

Question 12

Lung metastases

Answer 12

Most common site of metastatic neoplasms
Arrive by blood, lymphatics or direct continuity
Usually multiple discrete nodules (cannonball lesions) scattered thoughout all lobes
Peripheral lesions
Common primary sites- bowel, prostate, breast, kidney

Question 13

Pleural tumours

Answer 13

Secondary metastatic involvement more common than primary tumour
Most frequently lung or breast
Serous/serosanguinous effusion often present containing neoplastic cells
Primary tumour
Malignant mesothelioma

Question 14

Malignant mesothelioma

Answer 14

Increased incidence in people with exposure to asbestos
Latent period of 25-45 years
Diffuse lesion that spreads widely in the pleural space
Associated with extensive pleural effusion and direct invasion of thoracic structures
Plaques resulting from asbestos exposure can be found on the pleural surfaces
Histology - asbestos bodies are found in Presents with chest pain, dyspnoea, pleural effusions
50% die within 12 months of diagnosis
Invades lung directly
Often spread to hilar LN, and eventually to liver and other organs
Treatment:
Extra-pleural pneumonectomy, chemo, radiotherapy
Doesn’t often improve prognosis
Mesothelioma also arises in peritoneum, pericardium, genital tract
increased numbers in the lungs of patients with mesothelioma