Tumour Pathology Flashcards
What is a tumour ?
Neoplasm - new growth
Usually one cell type with supporting tissue structures.
(neoplastic cells and stroma)
Autonomous
Stroma
Connective tissue
Fibroblasts
Blood vessels
Immune cells
What does autonomous mean ?
Response to physiological stimuli lost or abnormal, allowing unregulated growth.
State a key risk factor for cancer
Age related incidence of cancer
There is a significant increase in the number of new cases, as the age at diagnosis increases.
State the most common cancer
Breast cancer
- much higher incidence in females
List the most common cancers
Breast
Prostate
Lung
Bowel
(all of these are organs with epithelial cells)
Feature of most common cancers
The most common cancers arise from tissue compartments or epithelial cells
State the 6 hallmarks of cancer
- Self sufficiency in growth signals
- Insensitivity to anti-growth signals
- Tissue invasion and metastasis
- Limitless replicative potential
- Sustained angiogenesis
- Evading apoptosis
Self sufficiency in growth signals
Doesn’t require signalling from the outside environment.
It can grow itself.
Insensitivity to growth signals
Provides its own proliferation signals and ignores anything else going on.
Tissue invasion and metastasis
Moves to other parts of the body
Limitless replicative potenital
Ability to keep growing.
Telomerase doesn’t degrade.
Sustained angiogenesis
Methods to get in blood supply for nutrients and oxygen.
State some features of benign tumour
Well circumscribed (rounded boundary)
Slow growth
No necrosis
Non-invasive
No metastasis
State some features of malignant tumour
Poorly circumscribed (poor boundary)
Rapid growth
Often necrotic
Invasive
Metastasis
Why is malignant cancer often necrotic ?
As malignant cells are fast growing and moving, they have used up oxygen and nutrients.
Clinical relevance of benign tumours
Does not invade surrounding structures
Does not metastasise
Clinical relevance of malignant tumours
Invades
Metastasises
State some clinical effects of benign tumours
- Space occupying
- Haemorrhage
- Hormone production
Describe the clinical effects of benign tumours
Space occupying
- Obstruction
- Epilepsy
- Conduction abnormalities (nerves)
Haemorrhage
- Pulmonary
- Gastrointestinal
Hormone production
- Pituitary
- Adrenal
- Endocrine pancreas
Describe malignant tumours
A colony of malignant cells established at a point distant from the original tumour.
How do malignant tumours spread ?
Directly invade locally
Via the lymphatics
Via the bloodstream (haematological)
Through body cavities (transcoelomic)
State some common secondary sites of spread
Prostate —> Bone
Lung —> Brain, Adrenals
Breast —> Lung, Liver, Bone, Brain
Ovary —> Peritoneal cavity
Secondary site for prostate cancer
Bone
Secondary site for lung cancer
Brain
Adrenals
Secondary site for breast cancer
Lung
Liver
Bone
Brain
Secondary site for ovarian cancer
Peritoneal cavity
State some names for tumour cells growing on the surface
Sessile - skin cancer
Pedunculated polyp - GI tract cancer
Papillary
State some names for tumour cells that move to surrounding tissue
Fungating
Ulcerated
State some names for tumour cells that grow in vessels
Annular
State some macroscopic features of benign tumours
Intact surface
Exophytic growth - grow on the outside
Homogenous cut surface
Circumscribed or encapsulated edge
State some macroscopic features of malignant tumours
Heterogenous cut surface due to necrosis
Ulcerated surface
Endophytic growth
Vascular permeation
Irregular infiltrative edge
Microscopic features of benign tumours
Resemble tissue of origin
Well circumscribed
Well differentiated
Minimal nuclear pleomorphism
Mitotic figures normal
NO necrosis
Microscopic features of malignant tumours
Variable resemblance
Poorly circumscribed
Variable differentiation
Variable pleomorphism may be anaplastic
Mitotic figures abnormal
Necrotic
Cytological features of malignancy
High nuclei-cytoplasmic ratio
Nuclear hyperchromasia
Nuclear pleomorphism
Abnormal chromatin structure
Abnormal mitotic figures
Differentiation
Resemblance to tissue of origin
Degree of differentiation allows GRADING - determined histologically
How is histological classification - grading - carried out ?
Degree of resemblance of tissue of origin allows grading.
Grade correlated broadly with clinical behaviour.
Precise classification important for planning treatment.
State the grading scale for malignant neoplasms
Grade:
1 - well differentiated
2 - moderately differentiated
3 - poorly differentiated
4 - nearly neoplastic
Classification of spread
Stage
- TNM staging
TNM staging system
T - tumour (1-4)
N - degree of lymph node involvement (0-2)
M - extent of distant metastases (0-2)
What staging system is used for colorectal cancer ?
Dukes’ Staging System for colorectal cancer
Describe Dukes’ Staging System for colorectal cancer
A - confined to bowel wall
B - through bowel wall but no lymph node involvement
C - lymph nodes involved
D - distant spread
Describe the nomenclature for benign tumours
Benign epithelial tumours can be:
- Papillomas
- Adenomas
Benign connective tissue tumours begin with the term denoting the cell of origin e.g. lipoma
Describe the nomenclature for malignant tumours
Malignant epithelial tumours are carcinomas
Malignant connective tissue tumours are sarcomas
State the major tumour categories
Epithelial origin
Connective tissue origin (mesenchymal)
Lymphoid/ haematopoetic origin
Benign squamous cell - nomenclature
Squamous cell papilloma
Benign transitional - nomenclature
Transitional cell papilloma
Benign basal cell - nomenclature
Basal cell papilloma
Benign glandular - nomenclature
Adenoma
Malignant squamous cell - nomenclature
Squamous cell carcinoma
Malignant transitional epithelia - nomenclature
Transitional cell carcinoma
Malignant basal cell - nomenclature
Basal cell carcinoma
Malignant squamous glandular - nomenclature
Adenocarcinoma
Benign smooth muscle - nomenclature
Leiomyoma
Benign striated muscle - nomenclature
Rhabdomyoma
Benign adipose tissue - nomenclature
Lipoma
Benign blood vessels - nomenclature
Angioma
Benign bone - nomenclature
Osteoma
Benign cartilage - nomenclature
Chondroma
Benign mesothelium - nomenclature
Benign mesothelioma
Benign synovium - nomenclature
Synovioma
Malignant smooth muscle - nomenclature
Leiomyosarcoma
Malignant striated muscle - nomenclature
Rhabdomyosarcoma
Malignant adipose tissue - nomenclature
Liposarcoma
Malignant blood vessels - nomenclature
Angiosarcoma
Malignant bone - nomenclature
Osteosarcoma
Malignant cartilage - nomenclature
Chondrosarcoma
Malignant mesothelium - nomenclature
Malignant mesothelioma
Malignant synovium - nomenclature
Synovial sarcoma
State some benign epithelial tumours
Papilloma (squamous, transitional)
Adenoma
State some malignant epithelial tumours
Squamous cell carcinoma
Transitional cell carcinoma
Adenocarcinoma
What can epithelial tumours be associated with ?
Non-invasive precursors
- Carcinoma in situ
- Intraepithelial neoplasia
State some benign mesenchymal tumours
Lipoma
Haemangioma
State some mesenchymal malignant tumours
Liposarcoma
Haemangiosarcoma
State some miscellaneous tumours
Melanoma
Lymphoma
Teratoma
Embryonal tumours - blastoma
Carcinoid tumours
Cysts
Describe teratoma
Contains elements of all 3 embryonic germ cell layers
- Of germ cell origin
- Benign and malignant forms
- Ovarian - almost always benign
- Testicular - more often malignant
Key feature of most tumours
Tumours have a clonal origin - they are derived from 1 abhorrent cellular change
Not all tumour cells are equal
Aide memoire for tumours
Incidence
Age
Sex
Geographical distribution
Predisposing factors
Macroscopic factors
Microscopic features
Spread
Prognosis
In a surgeons gown, physicians may make some progress
Describe how the concept of tumours having a clonal origin came about
Gene coded for by X chromosome
- Enzyme marker
- Lyon inactivation hypothesis
- Only 1 X chromosome in female cells is active
- One X chromosome is randomly switched off
Clonal origin
If the tumour arises from a single cell, if the tumour is from a clonal origin, then all the tumour cells will have the same enzyme marker.
CD24+
Non-tumorigenic
CD24-
Tumorigenic
