Growth disorders

Question 1

In considering disorders of growth, which one of the following statements is NOT correct?
a. Metaplasia, dysplasia and neoplasia all involve abnormal growth and differentiation.
b. Metaplasia is the irreversible transformation of one cell type into another.
c. Metaplasia can occur in the respiratory tract as a response to smoking.
d. Metaplasia represents an adaptive response of a tissue to stress.

Answer 1

Answer: b
“Metaplasia = REVERSIBLE transformation of one type of terminally diff cell into another type of fully diff cell which is usually less specialised” (slide 21 - neoplasia part 1)

• (d) Metaplasia “represents an ADAPTIVE (and reversible) response of a tissue to environmental stress / altered cellular environment” (slide 21)
• (c) “Change to squamous epithelium occurs in several mucosal in response to adverse stimuli - Respiratory epithelium of trachea and bronchi in smokers” (slide 22)

Question 2

Which one of the following statements regarding dysplasia is NOT correct?
a. May be caused by chronic inflammation or irritation of a tissue.
b. It is characterised by cellular atypic and decreased differentiation.
c. Dysplasia may be reversible in both early and late stages.
d. It is a premalignant condition.

Answer 2

Answer: c
Reversible only in EARLY stages.

• Dysplasia causes = “longstanding physical (irritation / chronic inflammation) or chemical (exposure to carcinogens) injury” (slide 23 - neoplasia part 1)
• Dysplasia recognisable by = increased growth, increased numbers of mitoses, cellular atypic and pleomorphism, and decreased differentiation. (slide 24)

Question 3

Which one of the following statements regarding neoplasia is NOT correct?
a. Carcinoma-in-situ is dysplastic change that involves the full thickness of an epithelial tissue.
b. A characteristic of neoplasia is the ability to become autonomous and persist in the absence of normal physiological stimuli.
c. Neoplasms result from genetic mutations in cells, resulting in abnormal and persistent growth.
d. All neoplasm have the inherent potential to invade and metastasise.

Answer 3

Answer: d
(Slide 28/26 - Neoplasia part 1)
* BENIGN neoplastic tumours are NON-INVASIVE and remain LOCALISED.
* Neoplastic cells in MALIGNANT tumours are able to INVADE and METASTASIS to other tissues.

• (a) “Malignant epithelial tumours = carcinomas” (slide 34 - neoplasia part 1)

Question 4

Which one of the following regarding malignant tumours is NOT correct?
a. Cancer accounts for about 20% of deaths in developed countries.
b. Malignancy can occur in infants.
c. Malignant neoplasms are likely to develop in around 50% of the human population.
d. Risk of malignancy increases with age.

Answer 4

Answer: c
“Malignant neoplasms develop in approximately 25% of the human population” (slide 29 - neoplasms part 1)

All given statements can be found on slide 29 (Incidence of tumours) - Neoplasms part 1.

Question 5

Which of the following statements regarding spread of a malignant tumour is NOT correct?
a. Cancer spreads throughout the body through the same routes that spread infections (e.g. blood, lymph).
b. Lungs are rarely a site for metastases.
c. Malignant invasion of lymphatic vessels may cause lymphoedema.
d. Any tumour that metastasises is malignant.

Answer 5

Answer: b
Lungs are a common site for blood-born mets. (+ liver, bone, brain, adrenals) (slide 27 - neoplasia part 2)

• (a) Routes of metastasis: Haematogenous ( via blood stream), Lymphatic ( via lymphatics), Trans-coelomic (through body cavities), Implantation (accidental spillage during surgery) - (slide 26 - neoplasia part 2)
• (d) “Any tumour that metastasises is malignant” (slide 25 - neoplasia part 2)