Respiratory: Pathology - Lung tumours Flashcards
What % of all lung tumours are bronchogenic carcinomas?
90-95%
What is the most frequently diagnosed major cancer worldwide?
Lung
What is the most common cause of cancer mortality worldwide, for both men and women?
Lung
Give four risk factors for lung carcinoma. Which is most important?
- Tobacco smoking (most common and important)
- Industrial exposures (e.g. radiation, asbestos - especially if coupled with smoking)
- Air pollution
- Genetics (oncogenes e.g. c-MYC, KRAS; loss of tumour suppressor genes e.g. p53, RB1)
Four main histologic types of lung carcinoma
- Adenocarcinoma
- Squamous cell carcinoma
- Small cell carcinoma
- Large cell carcinoma
How are lung carcinomas classified on the basis of their tendency to metastasise and response to chemotherapy?
Small cell: almost always metastatic, high initial response to chemotherapy
Non-small-cell: less likely to be metastatic, lower initial response to chemotherapy
What is the most common type of lung carcinoma in both men and women?
Adenocarcinoma
What is the typical location in the lung of adenocarcinoma?
More peripherally located and smaller
Histological features of lung adenocarcinoma
Varies: may be well-differentiates with glandular elements, or solid mass with occasional mucin-producing glands/cells
What is the difference between adenocarcinoma and squamous cell carcinoma in terms of rate of growth and tendency to metastasise?
Adenocarcinoma slow-growing but more likely to metastasise widely and earlier
Which of the subtypes of bronchogenic carcinoma has the strongest correlation with smoking?
Squamous cell carcinoma
Which of the subtypes of bronchogenic carcinoma has the highest frequency of p53 mutations?
Squamous cell carcinoma
What is the typical location in the lung of squamous cell carcinoma?
Historically tended to be central from segmental or subsegmental bronchi
Increasingly found peripherally
Histological features of squamous cell carcinoma
Keratinisation +/- intercellular bridges
May vary from well-differentiated keratinising neoplasms to anaplastic tumours with only focal differentiation
Which is the most malignant of the lung cancers?
Small cell carcinoma
What is the relationship of smoking to small cell carcinoma?
Strong relationship, only 1% are non-smokers
What is the typical location in the lung of small cell carcinoma?
May arise in major bronchi or in periphery
Histological features of small cell carcinoma
Distinctive cell type: small, oat-like with scant cytoplasm, ill-defined borders, and absent or inconspicuous nucleoli
Whole cell usually smaller than 3x resting lymphocytes
Necrosis common and extensive
May have neurosecretory granules and therefore most commonly cause paraneoplastic syndromes
What is large cell carcinoma? What is one important variant?
Probably represents very poorly differentiated adenocarcinoma or squamous cell carcinoma
One histological variant is large cell neuroendocrine tumour
What is the overall 5-year survival for bronchogenic carcinoma?
15%
Five complications of lung carcinoma related to tumour spread
- Airway obstruction leading to pneumonia, abscess, atelectasis
- Pleural invasion leading to effusion, pleuritis
- Pericardial invasion leading to pericarditits
- Nerve invasion: recurrent laryngeal (hoarseness), phrenic (diaphragm paralysis), cervical sympathetic trunks (Horner syndrome)
- Superior or inferior vena cava syndrome
Six hormones which may be released as paraneoplastic syndrome and their clinical consequences. Which of these are predominantly associated with small cell carcinoma and which are predominantly associated with squamous cell carcinoma?
- ADH: hyponatraemia (SIADH)
- ACTH: Cushing syndrome
- PTH, PGE2, some cytokines: hypercalcaemia
- Calcitonin: hypocalcaemia
- Gonadotropins: gynaecomastia
- Serotonin, bradykinin: carcinoid syndrome
Features of Horner syndrome
Unilateral ptosis, miosis, anhidrosis
Five systemic manifestations associated with lung carcinoma (but not strictly paraneoplastic syndromes)
- Lambert Eaton myasthenic syndrome
- Peripheral neuropathy
- Acanthosis nigricans
- Leukemoid reactions
- Hypertrophic pulmonary osteoarthropathy
What are Pancoast tumours and what syndrome do they present with?
Apical lung cancers in superior pulmonary sulcus which tend to invade neural structures around trachea
Can produce Horner syndrome (due to invasion into cervical sympathetic plexuses) and pain in ulnar nerve distribution
