Neoplasia

Question 1

How is neoplasia defined?

Answer 1

‘New growth’
Abnormal mass of tissue, the growth of which exceeded and is uncoordinated with that of normal tissues
It persists in the same excessive manner even after stimulus removal that evoked that change

Question 2

Compare benign and malignant neoplasms

Answer 2

Benign - Remains localised, cannot spread to other sites, can generally be surgically removed
Malignant - Lesion can invade and destroy adjacent structures and spread to distant sites and cause death

Question 3

What are some known facts about tumours?

Answer 3

• tumour growth is not reversible
• tumours are caused by changes in the DNA
• tumours are non-transmissible diseases

Question 4

What is a monoclonal proliferation?

Answer 4

All neoplasms arise from one mutated cell

Question 5

How are tumours classified?

Answer 5

Based on origin

• mesodermal
• epithelial
• round cell tumours

Question 6

What are leukemias?

Answer 6

Liquid tumours

Question 7

What are mixed tumours?

Answer 7

Arise from a single pluripotent cell capable of differentiating into many various cell types - epithelial and mesenchymal elements

Question 8

What is the name given to tumours composed of tissues from all different embryonic layers?

Answer 8

Teratomas

Question 9

What are the 2 possible tumour like lesions that will appear to be tumours but microscopically are not?

Answer 9

• Hamartomas: disorganised tissues in their normal anatomical location
• Choristomas: organised tissue found in abnormal anatomical locations

Question 10

Define anaplasia

Answer 10

Growth backwards - resemblance to embryonic forms that lac differentiation
Adult cells return to stem cell form
Only possible in cancerous cells

Question 11

Does anaplasia occur in benign or malignant tumours?

Answer 11

Malignant

Question 12

Give some morphological changes that are associated with anaplasia?

Answer 12

• Pleomorphism: variation in cell size and shape
• Loss of normal cell architecture
• Increased DNA and RNA content
• Higher proliferation activity - increased mitosis
• Loss of normal function
• Necrosis

Question 13

How is a benign tumour separated from the hosts tissue?

Answer 13

A rim of compressed connective tissue (fibrous capsule) develops which separates them

Question 14

How does a malignant tumour affect the surrounding tissue?

Answer 14

Progressive infiltration, invasion and destruction

Question 15

What is the first step involved in epithelial neoplasm invasion?

Answer 15

Reduce cell adherence by mutating the E-cadherin which holds them together

Question 16

What effect do neoplasms have to the inside of an epithelial cell once it has been detached?

Answer 16

• loss of polarity

- increased expression of integrins

Question 17

How do neoplasms migrate through the matrix?

Answer 17

Degrade the basement membrane and interstitial connective tissue by secreting proteolytic enzymes
Ameboid migration - secrete cytokines as squeeze through spaces in the matrix