Neoplasia 1 + 2 Flashcards
Define ‘neoplasia’
An abnormal mass of tissue
Growth is uncoordinated and exceeds that of normal tissues
Persists after removal of stimuli that initiated the change
Describe the growth pattern of benign tumours
Expansion
May be encapsulated
Localised
Slow growth rate
Describe the growth pattern of malignant tumours
Invasion/infiltration
No capsule
Metastasis
Rapid growth rate
Describe the histological appearance of a benign tumour
Resembles tissue of origin
Uniform cell/nuclear shape and size
Few mitoses
Describe the histological appearance of a malignant tumour
Variable resemblance to tissue of origin
Cellular and nuclear pleomorphism
Many mitoses, abnormal
How do you treat a benign growth?
Local excision
How do you treat a malignant growth?
Local excision and and chemotherapy or radiation if metastases present
What are the effects of a benign tumour?
Palpable lump, pressure, obstruction, function (especially hormone secretion)
The effects are not always benign
What is a squamous cell carcinoma?
A malignant tumour of the squamous epithelium
What is a papilloma?
A benign tumour of the squamous epithelium
What is an adenoma?
A benign tumour of the glandular epithelium
What is an adenocarcinoma?
A malignant tumour of the glandular epithelium
What does the suffix -sarcoma usually mean?
Malignant tumour
What is a lymphoma?
A malignant tumour of lymphoid tissue
What is leukaemia?
A malignant tumour of haematopoietic tissue
What is a melanoma?
A malignant tumour that develops from melanocytes
What causes benign tumours?
Little is known - may be inherited factors or viruses
What causes malignant tumours?
Chemical agents, physical agents, viruses
What are some examples of chemical carcinogens?
Tobacco, drugs, alcohol, asbestos
What are the two stages of chemical carcinogenesis?
- Initiation - permanent DNA damage (mutations)
- Promotion - agent promotes proliferation
Most chemicals are pro-carcinogen and require metabolic activation
Describe ‘initiation’ in chemical carcinogenesis
When a carcinogen induces a chemical change resulting in a neoplastic potential
Describe ‘promotion’ in chemical carcinogenesis
Another factor stimulates the imitated cell for division. Does not act on non-initiated cells.
Describe ‘progression’ in chemical carcinogenesis
Additional mutations occur resulting in malignancy
What are some examples of physical carcinogens?
Ionising radiation (e.g. UV light) - damages DNA causing mutations Radioactive metals and gases (e.g. radium)
Which are the most sensitive tissues to radiation?
Those in which cells are most rapidly renewed (embryonic tissues are the most sensitive)
Give some examples of viral carcinogenesis
- Epstein-Barr virus: Burkitt’s lymphoma, nasopharyngeal carcinoma
- Hepatitis B/C: Hepatocellular carcinoma
- Human papillomavirus (HPV): cervical and oropharyngeal carcinoma
What is the 2nd most frequent cause of death worldwide?
Cancer
What is the most common form of cancer?
Carcinoma - develops from epithelium