Neoplasms

Question 1

Why do tumours arise?

Answer 1

Due to accumulation of multiple genetic alterations (mutation, deletion, translocation) and epigenetic changes (methylation) in cells.

Question 2

What do these changes result in?

Answer 2

Abnormal (neoplastic) growth - forming mass of tumour cells that persists in the absence of the initiating causes.

Question 3

The structure of neoplastic cells comprise of…

Answer 3

Neoplastic cells and connective tissue stroma (provides vascular supply for growth).

Question 4

What makes neoplasms malignant?

Answer 4

Possess abnormal characteristics, i.e.:
- invade other tissues
- metastasise to other tissues

Question 5

Frequent malignancies in the UK

Answer 5

Lung CA
Colorectral CA
Breast CA + Prostate CA

Question 6

What is the role of the stroma?

Answer 6

Mechanical support
Intracellular signalling
Nutrition

Question 7

The process of stroma formation

Answer 7

Desmoplastic reaction (fibrous) due to induction of CT fibroblast proliferation by GFs from the tumour cells. = CANCER-ASSOCIATED FIBROBLASTS.

Question 8

In which type of CA are myofribroblats particularly abundant?

Answer 8

Breast CA - contractility= puckering and retraction of adjacent structures.

Question 9

What induces angiogenesis in tumours?

Answer 9

VEGF.

Question 10

What opposes the action of VEGF?

Answer 10

Angiostatin and endostatin. ? potential in CA therapy.

Question 11

What are the different shapes of tumours on a surface (i.e. GIT)?

Answer 11

Gross appearance can be:
- sessile
- polypoid (benign)
- papillary
- exophytic/fungating
- ulcerated (malignant)
- annular

Question 12

How neoplasms differ?

Answer 12

• loss/reduction of differentiation
• loss/reduction of cellular cohesion
• nuclear enlargement, hyperchromasia and pleomorphism
• increased mitotic activity

Question 13

What two factors are used in tumour classification?

Answer 13

Behaviour and histogenesis.

Question 14

Principle characteristics of benign tumours:

Answer 14

Growth rate: slow

Mitoses: infrequent

Histological resemblance to normal tissue: good

Nuclear morphology: near normal

Invasion: no

Metastases: never

Border: often circumscribed or encapsulated

Necrosis: rare

Ulceration: rare

Direction of growth on skin or mucosal surfaces: exophytic

Question 15

Principle characteristics of malignant tumours:

Answer 15

Growth rate: relatively rapid

Mitoses: frequent + atypical

Histological resemblance to normal tissue: variable, often poor

Nuclear morphology: Usually enlarged, hyperchromatic, irregular outline, multiple nucleoli, and pleomorphic (variable size and shape)

Invasion: yes

Metastases: frequent

Border: often poorly defined or irregular

Necrosis: common

Ulceration: common on skin or mucosal surfaces

Direction of growth on mucosal surfaces or skin: endophytic

Question 16

What clinical problems may arise from benign tumours?

Answer 16

Pressure on adjacent tissues.

Obstruction to the flow of fluid.

Production of a hormone.

Transformation into malignant neoplasm.

Anxiety.

Question 17

Histogenic classification

Answer 17

By tissue or cell of origin.

Histological resemblance to parent tissue allows for grading -> correlates with clinical behaviour.

Question 18

What are the major categories of histogenetic classification?

Answer 18

Carcinomas: epithelial tissue
Sarcomas: connective tissue
Lymphomas/leukaemias: lymphoid or haemopoietic organs.

Question 19

Malignant tumours degree of differentiation:

Answer 19

1 - well differentiated
2 - moderately differentiated
3 - poorly differentiated

Question 20

Benign epithelial and connective tissue tumours:

Answer 20

Papillomas (transitional or stratified squamous) and adenomas (glandular or secretory epithelium).

Question 21

Malignant epithelial and connective tissue tumours:

Answer 21

Carcinomas (non-glandular) adenocarcinoma (glandular) and sarcomas.

Question 22

Carcinoma in situ

Answer 22

Malignant - has not invaded through the basement membrane.

Question 23

A malignant lymphoma characterised by the presence of Reed-Sternberg cells

Answer 23

Hodgkin’s lymphoma

Question 24

Teratoma

Answer 24

Neoplasm of germ cell origin - all three germ layers.

Question 25

Blastomas

Answer 25

Arise in those below the age of 5.

• Retinoblastoma
• Nephroblastoma (Wilm’s tumour)
• Neuroblastoma (adrenal medulla or nerve ganglia
• Hepatoblastoma

Question 26

Mixed tumours

Answer 26

Characteristics combination of cell types - mixed parotid tumour.

Question 27

Endocrine tumours

Answer 27

From peptide hormone-secreting cells scattered diffusely in various epithelial tissue.

Insulinoma
Gastrinoma

Exceptions: medullary carcinoma of the thyroid gland - calcitonin producing.

Phaeochromocytome: adrenal medulla.

Question 28

Hamartomas

Answer 28

Tumour-like lesion - lacks autonomy of true neoplasm.

Pigmented naevi or adenochrondroma in lungs.

Question 29

Cysts

Answer 29

Fluid-filled space lined by epithelium.

Cysts types are:
Neoplastic (cystic teratoma)
Congenital (branchial cyst)
Parasitic (hydatid cysts)
Retention (pilar cysts)
Implantation (surgical)

Question 30

Neoplastic cells are…

Answer 30

Relatively or absolutely autonomous.

Unresponsive to extracellular growth factors.

Showing self-sufficiency in growth signalling.

Evade apoptosis.

Frequently have genomic instability.

Tumour products include fetal substances and unexpected hormones.

Question 31

Immortality of CA cells is due to…

Answer 31

Oncogenes + tumour supressor genes

Reduced apoptosis

Telomerase

Question 32

Genomic instability in tumour cells.

Answer 32

Nuclear hyperchromasia= exact multiples or chrosome gains/losses.

Pleomorphism

Translocation - Philadelphia chromosome t(9;22) CML.

Question 33

Mitotic figures in malignant tumours.

Answer 33

Abundant, grossly abnormal figures.

Question 34

Small cell carcinoma of the lungsecrete:

Answer 34

Substances inappropriate of their origin: ACTH and ADH.