S8) Introduction to Neoplasia Flashcards Preview

(LUSUMA) Pathological Processes > S8) Introduction to Neoplasia > Flashcards

Flashcards in S8) Introduction to Neoplasia Deck (38)
Loading flashcards...
1
Q

What is a neoplasm?

A

A neoplasm is an abnormal growth of cells that persists after the initial stimulus is removed

2
Q

What are malignant neoplasms?

A

A malignant neoplasm is an abnormal growth of cells that persists after the initial stimulus is removed and invades surrounding tissue, potentially spreading to distant sites

3
Q

What is a tumour?

A

A tumour is any clinically detectable lump or swelling

4
Q

Describe the relationship between the following terms:

  • Neoplasm
  • Cancer
  • Metastasis
A
  • Neoplasm: one type of tumour
  • Cancer: any malignant neoplasm
  • A metastasis: a malignant neoplasm that has spread from its original site to a new non-contiguous site
5
Q

What is dysplasia?

A

- Dysplasia is a pre-neoplastic alteration in which cells show disordered tissue organisation

  • It is not neoplastic because the change is reversible
6
Q

Explain how benign and malignant neoplasms show different behaviour

A

- Benign neoplasms remain confined to their site of origin and do not produce metastases

- Malignant neoplasms have the potential to metastasise

7
Q

Explain how benign and malignant neoplasms appear different to the naked eye

A
  • Benign tumours grow in a confined local area and so have a pushing outer margin (rarely dangerous)

- Malignant tumours have an irregular outer margin and shape and may show areas of necrosis and ulceration, if on a surface

8
Q

Describe the range of differentiation observed in malignant and benign neoplams respectively

A
  • A benign neoplasm has cells that closely resemble the parent tissue, i.e. they are well differentiated

- Malignant neoplasms range from well to poorly differentiated

9
Q

What are anaplastic cells?

A

Anaplastic cells are neoplastic cells with no resemblance to any tissue

10
Q

Describe what happens to neoplastic cells with worsening differentiation

A
  • Increases nuclear:cytoplasmic ratio
  • Increased nuclear staining (hyperchromasia)
  • More mitotic figures
  • Increasing variation in size and shape of cells and nuclei (pleomorphism)
11
Q

What is meant by the term grade?

A

Clinicians use the term grade to indicate differentiation e.g. high grade means poorly differentiated

12
Q

Explain how dysplasia can describe different degrees of differentiation

A
  • Dysplasia also represents altered differentiation
  • Mild, moderate and severe dysplasia indicates worsening differentiation
13
Q

What causes neoplasia?

A

Neoplasia is caused by accumulated mutations in somatic cells

14
Q

Explain how mutations in neoplastic cells are caused by initiators and promoters

A

The mutations are caused by initiators (mutagenic agents) and promoters, which cause cell proliferation

15
Q

What is the result of the combined efforts of intiators and promoters?

A

A combination of initiators and promoters results in an expanded, monoclonal population of mutant cells:

16
Q

Describe the different types of initiators and/or sources of mutation in neoplastic cells

A
  • Main initiatiors: chemicals, infections, radiation (some also act as promoters)
  • In some neoplasms, mutations can be inherited rather than from an external mutagenic agent
17
Q

What is progression?

A

Progression is the process through which a neoplasm emerges from its monoclonal population, characterised by the accumulation of yet more mutations

18
Q

What are monoclonal cells?

A

Monoclonal cells are a collection of cells which all originate from a single founding cell e.g. blood cells

19
Q

In four steps, explain how we know that neoplasms are monoclonal

A

⇒ An X-linked gene for the enzyme G6PD in tumour tissue from women has several alleles encoding different isoenzymes

⇒ In early female embryogenesis, one allele is randomly inactivated in each cell (lyonisation)

⇒ In heterozygous women, normal tissues will be patchwork of each type of isoenzyme (heat labile, heat stabile)

⇒ However, neoplastic tissues only express one isoenzyme (monoclonal)

20
Q

Which types of gene are affected by genetic alterations?

A

Genetic alterations affect proto-oncogenes and tumour suppressor genes

21
Q

Describe the genetic alterations which occur to proto-oncogenes and tumour suppressor genes

A
  • Proto-oncogenes become abnormally activated (become oncogenes), favouring neoplasm formation
  • Tumour suppressor genes, which normally suppress neoplasm formation, become inactivated
22
Q

How does one name benign and malignant neoplasms respectively?

A
  • Benign neoplasms end in –oma
  • Malignant neoplasms end in –carcinoma if it is an epithelial malignant neoplasm (90%)
  • Malignant neoplasms end in –sarcoma if it is a stromal malignant neoplasm
23
Q

In terms of invasion, what are the different types of carcinomas?

A
  • In-situ carcinomas: no invasion through epithelial basement membrane

- Invasive carcinomas: penetrated through basement membrane

24
Q

How does one classify epithelial benign neoplasms?

A

- Stratified squamous – squamous papilloma (any tumour with finger-like projections) e.g. skin, buccal mucosa

- Transitional – transitional cell papilloma e.g. bladder mucosa

- Glandular – adenoma e.g. adenomatous polyp of the colon

25
Q

How does one classify epithelial malignant neoplasms?

A
  • Stratified squamous – squamous cell carcinoma e.g. skin, larynx, oesophagus, lung

- Transitional – transitional cell carcinoma e.g. bladder, ureters

- Glandular – adenocarcinoma e.g. stomach, colon, lung, prostate, breast, pancreas, oesphagus

- Other – basal cell carcinoma e.g. skin

26
Q

Name the benign connective tissue neoplasms occurring in the following tissue structures:

  • Smooth muscle
  • Fibrous tissue
  • Bone
  • Cartilage
A

- Smooth muscle – leiomyoma

- Fibrous tissue – fibroma

- Bone – osteoma

- Cartilage – chondroma

27
Q

Name the benign connective tissue neoplasms occurring in the following tissue structures:

  • Fat
  • Nerve
  • Nerve sheath
  • Glial cells
A
  • Fat – lipoma
  • Nerve – neuroma
  • Nerve sheath – neurofibroma
  • Glial cells – glioma
28
Q

Name the malignant connective tissue neoplasms occurring in the following tissue structures:

  • Smooth muscle
  • Fibrous tissue
  • Bone
A

- Smooth muscle – leiomyosarcoma

- Fibrous tissue – fibrosarcoma

- Bone – osteosarcoma

29
Q

Name the malignant connective tissue neoplasms occurring in the following tissue structures:

  • Cartilage
  • Fat
  • Glial cells
A
  • Cartilage – chondrosarcoma
  • Fat – liposarcoma
  • Glial cells – malignant glioma
30
Q

Lymphoid & haematopoietic neoplasms are all regarded as malignant.

Explain how they are named

A
  • Lymphoid neoplasms are called lymphomas and occur in lymphoid tissue, usually in lymph nodes e.g. Hodgkins Disease & Non Hodgkins lymphoma
  • Haematopoietic neoplasms are called acute and chronic leukaemias, which occur in bone marrow, then abnormal cells enter blood
31
Q

What are lymphomas?

A

Lymphomas are malignant neoplasms of lymphocytes, mainly affecting lymph nodes

32
Q

What are leukaemias?

A

Leukaemias are malignant neoplasms of blood-forming cells arising in the bone marrow

33
Q

What are myelomas?

A

Myelomas are malignant neoplasms of plasma cells

34
Q

How do germ cell neoplasms arise?

A

Germ cell neoplasms arise from pluripotent cells, mainly in the testis or ovary

35
Q

Identify some examples of germ cell neoplasms

A

- Testis: malignant teratoma, seminoma (malignant)

- Ovary: benign teratoma (dermoid cyst)

36
Q

How do neuroendocrine tumours arise?

A

Neuroendocrine tumours arise from cells distributed throughout the body

37
Q

Provide some examples of neuroendocrine tumours

A
  • Carcinoid tumours (various organs)
  • Phaeochromocytoma (adrenal)
  • Small cell carcinoma (bronchus)
38
Q

What are blastomas?

A

Blastomas are malignant neoplasms which occur mainly in children and are formed from immature precursor cells e.g. nephroblastoma