Cancer Definitions and Nomenclature

Question 1

Define the term “metaplasia”.

Answer 1

An adaptive and reversible change in which one adult cell type (usually epithelial) is replaced by another adult cell type.

Question 2

Give one example of metaplasia as a) a physiological response and b) a pathological response.

Answer 2

a) Cervical changes in the female during puberty.

b) Barrett’s oesophagus in response to continued presence of acid in the oesophagus.

Question 3

Define the term “dysplasia”.

Answer 3

An abnormal pattern of growth in which some of the cellular and architectural features of malignancy are present

The pre-invasive stage presents with intact basement membrane.

Question 4

Define the term “neoplasm”.

Answer 4

An abnormal, autonomous proliferation of cells unresponsive to normal growth control mechanisms.

Question 5

What features differentiate benign tumours from malignant ones?

Answer 5

1. Do no invade or metastasise
2. They are encapsulated
3. They are usually well-differentiated
4. They are slow-growing
5. They usually have normal mitoses

Question 6

List the main features of dysplasia.

Answer 6

Loss of architectural orientation
Loss in uniformity of individual cells
Hyperchromatic, enlarged nuclei
Mitotic figures: abundant, abnormal, in places where not usually found

Question 7

Where is dysplasia commonly found?

Answer 7

Cervix - HPV infection
Bronchi - Smoking
Colon - UC
Larynx - Smoking
Stomach - Pernicious anaemia
Oesophagus - Acid reflux

Question 8

What are the key features of malignant tumours?

Answer 8

1. They invade surrounding tissues
2. They spread to distant sites (metastasis)
3. They are not encapsulated
4. They are well to poorly differentiated
5. They are rapidly growing
6. They show abnormal mitoses

Question 9

What is a metastasis?

Answer 9

Discontinuous growing colony of tumour cells, at some distance from the primary cancer.

Question 10

Which factors determine the locations of metastases?

Answer 10

Lymphatic and vascular drainage of primary site.

Lymph node involvement has a worse prognosis.

Question 11

Benign epithelial tumours

Answer 11

Of surface epithelium = Papilloma
–> E.g skin, bladder

Of glandular epithelium = Adenoma
–> E.g stomach, thyroid, colon, kidney, pituitary, pancreas

Question 12

What is a carcinoma?

Answer 12

Malignant tumour derived from epithelium.

Squamous cell
Adenocarcinoma,
Transitional cell
Basal cell carcinoma

Question 13

What is an osteoma?

Answer 13

A benign soft tissue tumour.

Question 14

What is a sarcoma?

Answer 14

A malignant tumour derived from connective tissue (mesenchymal) cells.

Fat = LipoSARCOMA
Bone = OsteoSARCOMA
Cartilage = ChondroSARCOMA
Muscle 
--> Striated  = RhabdomyoSARCOMA, 
--> Smooth = LeiomyoSARCOMA
Nerve sheath  = Malignant Peripheral Nerve Sheath Tumour

Question 15

What is lymphoma?

Answer 15

A malignant tumour of lymphocytes (usually) in lymph nodes

Question 16

What is leukaemia?

Answer 16

A malignant tumour of bone marrow derived cells which circulate in the blood.

Question 17

What is a teratoma?

Answer 17

A tumour derived from germ cells, which have the potential to develop into tumours of all three germ cell layers (ectoderm, mesoderm, endoderm)

Question 18

What is a hamartoma?

Answer 18

A localised overgrowth of cells and tissues native to the organ.
The cells are mature (cytologically normal) but architecturally abnormal.

It is common in children, and should stop growing when they do.

Examples: bile duct hamartomas, bronchial hamartomas

Question 19

What is lymphoma?

Answer 19

A malignant tumour of lymphocytes (usually) in lymph nodes

Question 20

What is leukaemia?

Answer 20

A malignant tumour of bone marrow derived cells which circulate in the blood.

Question 21

Explain what “grade” and “stage” mean in reference to tumours.

Answer 21

The grade of a tumour describes its degree of differentiation.

The stage of a tumour describes how far it has spread.

Tumours of higher grade (i.e. more poorly differentiated) tend to be of higher stage (i.e. spread further), but stage is more important than grade in determining prognosis.

Question 22

What criteria are used to assess the differentiation of a malignant tumour?

Answer 22

1. Evidence of normal function still present (e.g production of keratin, mucin, bile, hormones)
2. Various grading systems - for Ca breast, prostate, colon
3. No differentiation –> ANAPLASTIC carcinoma

Question 23

What is the TNM system?

Answer 23

The Tumour, Node, Metastasis (TNM) system can be applied, and individualised, to tumour in all sites.

Question 24

Explain what “grade” and “stage” mean in reference to tumours.

Answer 24

The grade of a tumour describes its degree of differentiation.

The stage of a tumour describes how far it has spread.