Cellular pathology of cancer

Question 1

Define metaplasia

Answer 1

When cells are faced with physiological or pathological stresses, they respond by adapting in any of several ways, one of which is metaplasia.
Metaplasia is a reversible change in which one adult cell type (usually epithelial) is replaced by another adult cell type

Question 2

Give two examples of metaplasia, one pathological and one physiological.

Answer 2

Barrett’s Oesophagus – gastro-oesophageal reflux can change the stratified squamous epithelium of the distal oesophagus to simple columnar
Cervix during pregnancy – the cervix opens up and the columnar epithelium of the endocervical canal is exposed to the acidic uterine fluids making it squamous

Question 3

What are the two types of metaplasia that can take place in Barrett’s Oesophagus?

Answer 3

Gastric metaplasia – stratified squamous to simple columnar

Intestinal metaplasia – goblet cells begin to appear

Question 4

Define dysplasia

Answer 4

An abnormal pattern of growth in which some of the cellular and architectural features of malignancy are present; pre-invasive stage with intact basement membrane

Question 5

Describe some general features of dysplastic growth

Answer 5

• Enlarged hyperchromatic nuclei
• Mitotic figures (chromosomes visible as tangled, dark-staining threads) are abundant, abnormal and in places where not usually found
• Loss of architectural orientation
• Loss in uniformity of individual cells

Question 6

What is the difference between low and high-grade dysplasia?

Answer 6

They both show changes of dysplasia but the changes are more severe in high-grade dysplasia
High-grade has a high risk of progression to cancer

Question 7

Neoplasia, tumour and malignancy all generally refer to what?

Answer 7

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

Question 8

What are the main features of benign tumours that separate them from malignant tumours?

Answer 8

They do not metastasise
They do not invade
They also are usually encapsulated (except for fibroids in the uterus), slow growing and have normal mitoses

Question 9

Under what conditions can benign tumours be dangerous? Give examples

Answer 9

If they:

• are in a dangerous place e.g. meninges, pituitary
• secrete something dangerous e.g. insulinoma
• get infected e.g. in bladder
• bleed e.g. in stomach
• rupture e.g. liver adenoma
• get twisted (tort) e.g. ovarian cyst

Question 10

State the 6 features of malignant tumours

Answer 10

1. Invade surrounding tissues
2. Spread to distant sites
3. No capsule
4. Well to poorly differentiated
5. Rapidly growing
6. Abnormal mitoses

Question 11

Define metastasis. What does it depend on?

Answer 11

A discontinuous growing colony of tumour cells at a distance from the primary cancer

• Depends on the lymphatic and vascular drainage of the primary site; lymph node involvement has a worse prognosis

Question 12

What characterises a well differentiated tumour? State the term given to tumours that show little or no differentiation?

Answer 12

• Grow and spread at lower rate (less aggressive)
• Cells are mature
• Close resemblance to the corresponding normal tissue
• May be normal function present

Anaplastic

Question 13

What are the two different types of benign epithelial tumour?

Answer 13

Papilloma – of the surface epithelium

Adenoma – of glandular epithelium

Question 14

Define carcinoma.

Answer 14

Malignant tumour derived from the epithelium

Question 15

What are the different types of carcinoma?

Answer 15

• Basal cell carcinoma
• Squamous cell carcinoma
• Transitional cell carcinoma (transitional epithelium is found in the bladder)
• Adenocarcinoma

Question 16

State some different types of benign soft tissue tumour.

Answer 16

Osteoma –bone
Lipoma - fat
Leiomyoma – smooth muscle

Question 17

Define sarcoma.

Answer 17

Malignant tumour derived from connective tissue (mesenchymal) cells

Question 18

What are the names given to malignant tumours of striated muscle, smooth muscle and the nerve sheath?

Answer 18

Striated muscle = rhabdomyosarcoma
Smooth muscle = leiomyosarcoma
Nerve sheath = Malignant peripheral nerve sheath tumour

Question 19

Define leukaemia.

Answer 19

Malignant tumour of bone marrow derived cells which circulate in the blood

Question 20

Define lymphoma

Answer 20

Malignant tumour of lymphocytes (usually) in lymph nodes

Question 21

Define teratoma

Answer 21

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

Question 22

What is an important difference between gonadal teratomas in men compared to women?

Answer 22

Gonadal teratomas in men are almost always malignant

Gonadal teratomas in women are almost always benign

Question 23

Define hamartoma.

Answer 23

Localised overgrowth of cells and tissues native to the organ (i.e. cells are mature but architecturally abnormal)

Question 24

Which group of the population is hamartoma common in?

Answer 24

It is common in children (hamartoma usually stops growing when the children stop growing)

Question 25

What is the difference between grading and staging?

Answer 25

Grading = describes the degree of differentiation of tumour
Staging = how far the tumour has spread

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

Question 26

What are the grading systems for breast and prostate cancer?

Answer 26

Breast –Nottingham scoring system

Prostate – Gleason grading system