Neoplasia Flashcards
Define neoplasia
An abnormal mass of tissue, the growth of which exceeds that of the normal tissue and persists in the same excessive manner after cessation of the stimuli which evoked the change
Define differentiation
The extent to which neoplastic cells resemble comparable normal cells, both morphological and functionally
Define anaplasia
Lack of differentiation characterised by:
Pleonorphism
Abnormal nuclear morphology
Mitoses
Loss of polarity
Other changes
Define pleomorphism
Variation in size and shape of cells and nuclei
Define dysplasia
A loss in the uniformity of the individual cells as well as a loss in their architectural organisation
Mild-moderate dysplasia is reversible if the stimulus is removed
Define grading
An estimate of the clinical gravity of a tumour based on the degree of differentiation and number of mitoses within the tumour
Define staging
An estimate of the clinical gravity of a tumour based on the anatomical extent of the tumour
2 systems:
TNM - tumour nodes metastases
AJC - American joint committee
In tumours what is parenchyma
Proliferating neoplastic cells
In tumours what is stroma
Non- neoplastic supportive tissue eg connective tissue, blood vessels
Local invasion in benign tumours
Most benign tumours grow as cohesive expansile masses that develop a capsule
Do not penetrate the capsule
Provides a plane for surgical cleavage
Invasion of malignant neoplasms
Infiltrate and destroy normal tissue around them
Surgical treatment requires removal of a considerable margin of
What are the four steps of the process of invasion of the cellular matrix
- Detachment of tumour cells from each other
- Attachment to matrix proteins binding to laminin, fibronectin via cell surface receptors
- Degradation of the extracellular matrix
- Migration of tumour cells
What is the single most important feature distinguishing benign from malignant tumours
Metastasis
What are the 3 routes of metastasis
- Spread into body cavities
- Invasion of lymphatics
- Haematogenous spread
Mechanisms dictating the distribution of metastases
- Tumour cell adhesion molecules
Ligands that are normally expressed in target organ cells - Chemokines
For target organs present in the tumour cells - Chemoattractants
From target cells
What is carcinogénesis
The clonal growth of cells that have incurred mutations in four classes of genes
- those that regulate cell growth (proto-oncogenes and tumour supperessorngenes)
Those that regulate apoptosis and dna repair
Carcinogenic chemical agents
- Alkylation agents - cyclophosphamide busulfan
- Aromatic hydrocarbons - cigarette smoke
- Azo dyes - beta-naphthylamine
- Naturally occurring carcinogens - aflatoxin B produced by fungus aspergillus flavus, hepatocellular cancer
- Nitrosamines and amides - can’t be synthesised in GI tract
- Miscellaneous - asbestos, nickel
Radiation carcinogenic agents
UVB = skin cancer
Ionising radiation = myeloid leukaemias, thyroid cancer
Viral carcinogenic tumours
HPV - cervical
EBV - Burkitt lymphoma, nasopharyngeal ca, B cell lymphoma
HepB - liver
HTLV -1 = leukaemia
H.pylori
Define paraneoplastic syndrome
Symptom complexes that occur in patients with cancer that cannot be readily explained by local or distant spread of the tumor or by the release of hormones normally released by the tissue of origin
Define endocrinopathies
Some nonendocrine cancers produce hormones or hormone like factors
4 examples of endocrinopathies
- Small cell lung cancer produce adrenocorticotropic hormones = Cushing syndrome
- Small cell lung cancer produce ADH = SIADH
- Carcinoid tumours produce serotonin and bradykinin = vasoactive affects
- Hypercalacaemia - elaboration of PTH- like peptides or TNF alpha = resorption of bone
The oral contraceptive pill is protective against..
Endometrial and ovarian carcinomas
Most common type of thyroid cancer is ..
Papillary (75-85%)
