Pathology of Pulmonary Neoplasia Flashcards
What is the aetiology of pulmonary neoplasia?
Smoking.
Air pollution.
Asbestos.
Environmental radon (radiation).
Occupational exposure (chromates, hydrocarbons, nickel).
Pulmonary fibrosis.
What are some statistics about how smoking affects lung cancer?
> 85% of cancers are attributable to lung cancer.
10% of smokers get lung cancer.
Females are more susceptible.
Risk is related to consumption.
Second-hand smoke increases risk by 50-100%, and causes >25% of non-smoking lung cancers.
What is the current state of tobacco consumption?
In some countries - increasing.
Abstinence causes the risk to decrease slowly, but genomic damage persists.
There is no safe smoking threshold.
What chemicals are found in tobacco smoke?
~60 recognised carcinogens.
Has effects on lung epithelium.
Affects the multi-hit theory of carcinogenesis.
Activates pro-carcinogens (predisposed by inherited polymorphisms - pro-carcinogen metabolism, nicotine addiction).
What is the pathway of carcinogenesis in the lung periphery?
Bronchioloalveolar epithelial stem cells transform into atypical adenomatous hyperplasia.
This becomes adenocarcinoma in situ, which develops into invasive adenocarcinoma (and becomes invasive squamous cell carcinoma).
What is the pathway of carcinogenesis in the central lung airways?
Bronchial epithelial stem cells transform into bronchial basal cell hyperplasia.
This becomes squamous dysplasia and carcinoma in situ, which develops into invasive squamous cell carcinoma.
What are the different types of lung ‘tumours’?
Metastases to the lung (common).
Benign causes of mass lesions.
Carcinoid tumours (<5% of lung neoplasms, low grade malignancy).
Tumours of bronchial glands (rare - adenoid cystic carcinoma, mucoepidermoid carcinoma, benign adenomas).
Lymphoma.
Sarcoma.
What are the main types of lung carcinomas?
Adenocarcinoma (41%).
Squamous cell carcinoma (40%).
Small cell carcinoma (15%).
Large cell carcinoma (4%).
Bronchioloalveolar cell carcinoma was a subtype of adenocarcinoma but is now called adenocarcinoma in situ.
What are the histological types of lung carcinoma?
~15% - SCLC.
~85% - NSCLC (adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and others).
Particular types of NSCLC cannot be distinguished from one another on small biopsy samples.
What is the natural history of primary lung cancer?
Grows ‘clinically silent’ for many years.
Presents late in its natural history.
May have few, if any, signs or symptoms until the disease is very advanced.
May be found incidentally during an investigation for something unrelated.
Symptomatic lung cancer is generally fatal.
What bronchial obstruction can lung cancer cause?
Local.
Collapse.
Endogenous lipoid pneumonia.
Infection/abscess.
Bronchiectasis.
What nerve damage can lung cancer cause?
Local.
Phrenic - diaphragmatic paralysis.
Left RLN - hoarse, bovine cough.
Brachial plexus - Pancoast tumour.
Cervical sympathetic - Horner’s syndrome.
What other local effects can lung cancer cause?
Pleural inflammation and malignancy.
Direct chest wall invasion.
Mediastinum - SVC, pericardium.
LN metastases - mass effect, lymphangitis carcinomatosa.
What distant effects can lung cancer cause?
Distant metastases (liver, adrenals, bone, brain, skin).
Secondary to local effects (neural and vascular).
Non-metastatic effects.
What are the non-metastatic paraneoplastic effects of lung cancer?
Skeletal - clubbing, inflammation.
Endocrine - ACTH, SIADH, PTH, gynecomastia.
Neurological - polyneuropathy, encephalopathy, cerebellar degeneration, myasthenia.
Cutaneous - acanthosis nigricans, dermatomyositis.
Haematologic - granulocytosis, eosinophilia.
Cardiovascular - thrombophlebitis migrans.
Renal - nephrotic syndrome.
