Bronchogenic Carcinoma causes, pathology, classification and spread

Bronchogenic Carcinoma is the most common malignancy in males, it accounts for 32% of all cancer deaths in men, 85% of patients die within 5 years.

Causes and incidence of Bronchogenic carcinoma

 (no definite aetiology)
• Male > female
• Peak incidence occurs between ages 55 and 65 years.
• Predisposing factors:
• The major cause is tobacco use particularly cigarette smoking
• 3,4 benzpyrine is the carcinogenic substance especially if combined with asbestos.
• Air pollution (coal combustion, cadmium and radon).
• Occupation inhaled substances e.g asbestos, nickel and arsenic.
• Radiation e.g atomic bomb survivors, uranium miners.
• Genetic mechanism e.g dominant oncogenes and loss of tumour suppressor genes.

 The risk is increased 40 times fold for man smoking two packs /d. for 20 years .

Pathology

1- Central or hilar type in a main bronchus, it invades the mediastinum early
2- Peripheral in small bronchus, it invades pleura early
3- Pancoast tumour, it is apical and invades the thoracic inelt early.
Naked eye appearance : Fungating mass - Malignant ulcer - Infiltrative type
Microscopic:
WHO classification
WHO-classification-of-Bronchogenic-Carcinoma


Methods of Spread of  Bronchogenic carcinoma

Direct                   : lung, pleura, mediastinum, brachial plexus, sympathetic chain and phrenic nerve.

Lymphatic spread  :  - Hilar & mediastinum, then cervical L.N.
                                  -Retrograde lymphatic ==> (lymphangitis carcinomatosa) ==> cor pulmonale
Haematogenous    :   Bones, liver, brain

Bronchoalveolar cell carcinoma (Bronchiolar carcinoma) arising in the terminal bronchioloalveolar regions accounts for 1-2% of lung tumors.
 It may be a peripheral solitary nodule or diffuse nodular lesion. It occurs in men and women equally and
usually not associated with smoking.
It may be associated with expectoration of a large volumes of mucoid sputum.
Important articles to read : 
• Manifestations of Bronchogenic carcinoma (clinical picture)

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