Neoplasia II

Question 1

In what ways can benign tumours be dangerous?

Answer 1

• Hormone production e.g thyroid adenoma
• Pressure effect on adjacent tissue e.g intracranial tumours

Question 2

What are the effects of malignant tumours?

Answer 2

• Pain, ulceration and haemorrhage
• Metastatic effects
• Inappropriate hormone production, fever, stenosis

Question 3

What are paraneoplastic syndromes?

Answer 3

• Occur at distal sites from tumour and its metastasis
• Symptoms secondary to substances secreted by tumour/adverse effects of antibodies directed against tumours
• EXAMPLE: Venous thrombosis - from pancreatic carcinoma - caused by tumour products activating clotting

Question 4

Outline the pathway for diagnosis of cancer

Answer 4

• Clinical presentation
• Biopsy and fine needle aspiration
• Investigation of tumour through scanning
• Tumour is assessed to determine grade and stage

Question 5

What does tumour grade and stage refer to?

Answer 5

• Tumour grade, biological nature of tumor, based on histological analysis e.g pleomorphism
• Tumour stage, extent of tumour: size and spread

Question 6

Describe the following tumour mode of spread - local invasion.

Answer 6

• Spread of tumour into surrounding tissue by direct route
• Invasion of overlying skin by breast carcinoma
• Tumour size and spread forms basis of staging

Question 7

Describe the following tumour mode of spread - lymphatic spread

Answer 7

• Cancer spreads via lymphatic vessels draining site of primary tumour
• Neoplastic cells conducted to local nodes and form secondary tumours
• Basis of N staging (number of nearby lymph nodes that have cancer) - TMN classification

Question 8

Describe the following tumour mode of spread - vascular spread

Answer 8

• Tumours spread via veins draining primary site
• Gut tumours spread via portal vein
• In systemic circulation, neoplastic cells trapped in lung forming pulmonary metastases
• Basis of M staging - i.e has it metastasised?

Question 9

Describe the following tumour mode of spread - transcoelomic spread

Answer 9

• Tumours spread across coelomic spaces
• Carcinoma of ovary spready transcoelomically forming metastatic deposits on peritoneal surfaces

Question 10

Describe the molecular alterations of normal cells to form neoplastic cells.

Answer 10

• Telomerase expression causes biological immortality of cells.
• Inactivation of tumour suppressor genes e.g p53. Removal of growth inhibition
• Oncogene activation causing autocrine growth stimulation
• Forms neoplastic cells which proliferate

Question 11

What factors can initiate transformation of normal cells to neoplastic cells?

Answer 11

• Carcinogens
• Chemical, radiation and viral factors

Question 12

Describe histological features and outcome of dysplasia.

Answer 12

• Disordered development of epithelium
• Loss of cellular uniformity. Increase in mitotic figures
• May progress to malignancy but not always
• Reversible if inciting agent removed

Question 13

Describe how the epithelium is affected by neoplasia.

Answer 13

• NORMALLY - normal stratified epithelium
• DYSPLASIA - minor loss of stratification
• INVASION - erosion of basement membrane. Neoplastic cells gain access to vascular channels

Question 14

Describe the mechanism of tumour invasion and metastasis.

Answer 14

• Cancer cells become capable of invasion
• Tumour cell adhesion molecules bind to underlying extracellular matrix.
• Tumour cells disrupt and invade matrix.
• Tumour cells metastasise by way of blood vessels

Question 15

Describe how angiogenesis develops.

Answer 15

• Primary tumor forms
• Invasion of basement membrane by tumor cells
• Intravasation and interaction with. lymphoid cells
• Angiogenesis induced.
• Metastatic tumor forms causing tissue destruction.