10. Respiratory tract: neoplastic disease Flashcards Preview

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Lung tumours

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


Lung carcinomas

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)


Risk factors

Industrial hazards
High dose ionising radiation
Diesel exhaust/air pollution
Family history



Statistical evidence
87% of lung carcinoma in active smokers/recently stopped smoking
10 fold ↑ risk for average smokers, 60 fold ↑ risk for heavy smokers (>40/day for several yrs)
3000 non smokers die of lung ca/year – passive smoking
Cigar/pipe - ↑ risk, but less so than cigarettes
Clinical evidence
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


Clinical details

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%)


Local effects of lung tumour spread

Pneumonia, abscess, lobar collapse = Obstruction of airway
Pleural effusion = Spread into pleura
Hoarseness = Recurrent laryngeal nerve invasion
Dysphagia = Oesophageal invasion
Diaphragm paralysis = Phrenic nerve invasion
Rib destruction = Chest wall invasion
SVC syndrome = SVC compression by tumour
Horner syndrome = Sympathetic ganglia invasion
Pericarditis, tamponade = Pericardial involvement


Paraneoplastic syndromes

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


Lung carcinoma

Staging – TNM staging

Treatment –
Chemotherapy – targeted therapy for EGFR mutation

15% overall 5-year survival
(48% for cases detected when still localised) adenocarcinoma, SCC – slightly better prognosis, tend to remain localised longer


Lung Carcinoma – Staging - TNM

T’ - Primary tumour size/degree of invasion?

‘N’ – Lymph nodes positive or not ?

‘M’ – Distant metastases or not ?


Size cut-offs for T1, T2 and T3 tumours

>7cm T3



Small cell carcinoma (20-25%)

Non-small cell carcinoma
Squamous cell carcinoma (25-40%)
Adenocarcinoma (25-40%)
Large cell carcinoma (10-15%)

Combined carcinoma


Small cell carcinoma (1)

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)


Small cell carcinoma (2)

Cells with little cytoplasm
Finely granular nuclear chromatin (“salt + pepper”)
Absent or inconspicuous nucleoli
Can be pure or combined (with any other non-small cell type)


Other histological features

Nuclear molding
Crush artifact
High mitotic index


Squamous cell carcinoma (1)

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


Squamous cell carcinoma (2)

Usually arise centrally from the bronchi
Keratinisation and/or intercellular bridges
2/3 central (segmental bronchi)
90% of cases are smokers


Adenocarcinoma (1)

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


Adenocarcinoma (2)

2/3 peripheral
Grow more slowly than squamous cell carcinomas but tend to metastasise widely and earlier
Peripheral adenocarcinomas are sometimes associated with areas of scarring


Large cell carcinoma

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


Lung metastases

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


Pleural tumours

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


Malignant mesothelioma (1)

Increased incidence in people with exposure to asbestos
Lifetime risk in heavily exposed individuals as high as 7-10%
Latent period of 25-45 years
No increased risk in asbestos workers who smoke
Diffuse lesion that spreads widely in the pleural space
Associated with extensive pleural effusion and direct invasion of thoracic structures


Malignant mesothelioma (2)

Plaques resulting from asbestos exposure can be found on the pleural surfaces
Histology - asbestos bodies are found in increased numbers in the lungs of patients with mesothelioma
Affected lung is ensheathed by a thick layer of soft, gelatinous, greyish pink tumour tissue


Malignant mesothelioma (3)

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
Extra-pleural pneumonectomy, chemo, radiotherapy
Doesn’t often improve prognosis
Mesothelioma also arises in peritoneum, pericardium, genital tract