CA3: Pathology of neoplasia Flashcards
1. Define: tumour, neoplasm, benign, malignant, histogenesis, differentiation, metastasis 2. Give classification of benign and malignant neoplasms according to their cells of origin 3. Compare and contrast the pathological features of benign and malignant neoplasms 4. Describe the effects of neoplasms on the host
Define tumour
Swelling
Define neoplasm
Abnormally excessive out of control tissue growth continuing in absence of the initiating stimulus
To determine if a swelling is neoplastic, a biopsy must be taken as the tumour could be a result of an access/infection
What is neurofibromatosis
Benign tumour of nerve sheath origin
Why can some benign neoplasms be life threatening and give examples of this
Due to their site e.g.
- Meningioma causes increased intracranial pressure
- compressive effect on brain
- impacts vascular + CSF inflow and outflow - Insulinoma in islets of Langerhans produces insulin so can cause hypoglycaemia
What is basal cell carcinoma
Malignant tumour of the skin due to sun exposure; there is no metastasis and it is of localised origin so can be easily removed
- even though this is malignant it doesn’t cause much harm and only causes significant damage when left alone
What can neglected basal cell carcinoma result in
Erosion into the bone and localised spreading
Describe how normal squamous epithelium (skin) appears under a microscope and how this is different in squamous cell neoplasms
Normally; cells originate from basal zone and proliferate here, they will then mature and migrate to the surface and this is where the nucleus is lost from the cell and the cytoplasm will accumulate keratin
Neoplasm; protein on the surface has keratin and there are intercellular prickles (bridges), the cells are disorganised and the nucleus is enlarged
What is differentiation in terms of neoplasms
The degree to which a neoplasm resembles the normal cell of origin
- Well differentiated = close resemblance
- Poorly differentiated = little resemblance
This grading gives a prognostic indication of how the neoplasm will behave
Describe the visible differences in well and poorly differentiated adenocarcinoma
Well = tubular structures seen as it is a glandular epithelium
Poor = infiltration of other cells into the fibromuscular tissue, holes can be seen
What is anaplasia
Complete lack of differentiation in a neoplasm
What is small cell anapaestic carcinoma
Type of lung cancer derived from neuroendocrine cells where there is no differentiation microscopically and there is no cohesive structure, cells are present in sheets
A diagnosis cannot be made on biopsy alone
What is squamous cell papilloma
Benign neoplasm in stratified squamous epithelium e.g. skin
What is transitional cell papilloma
Benign neoplasm in transitional cell epithelium e.g. urogenital tract
What is an adenoma
Benign neoplasm of glandular epithelium e.g. in GIT
What is a lipoma
Benign connective tissue neoplasm in fat cells; this will be well circumscribed, have a uniform cut surface and be yellow in appearance due to being fat filled
What is leiomyoma
Benign connective tissue neoplasm in smooth muscle
What is neurofibroma
Benign connective tissue neoplasm in nerve
What is rhabdomyoma
Benign connective tissue neoplasm in striated muscle
What is haemangioma
Benign connective tissue neoplasm in the endothelial lining of blood vessels
What is lymphoma
Malignant neoplasm of lymphoid tissue
What is myeloma
Malignant neoplasm of plasma cells in the bone marrow
What is melanoma
Malignant neoplasm of melanocytes in skin
What is mesothelioma
Malignant neoplasm in the pleural lining (creosol surface)
What do malignant neoplasms of the epithelial tissue end in
carcinoma
What do malignant neoplasms of connective tissue end in
sarcoma
What do malignant neoplasms of embryonic tissues end in
blastoma
What is nephroblastoma
Malignant embryonic neoplasm of kidney
What is neuroblastoma
Malignant embryonic neoplasm of neural tissue
What is retinoblastoma
Malignant embryonic neoplasm of the retina
What are germ cell neoplasms
Germ cells are found in the ovary and testes and the neoplasms derived from them care called teratomas
What are teratomas
These are neoplasms which differentiate along more than one germ cell line and can be benign or malignant
What are the macroscopic differences between benign and malignant tumours
Benign = well-defined outline, smooth surface Malignant = irregular, ill-defined outline, craggy surface
What are the microscopic differences between benign and malignant tumours
Benign = blunt, pushing Malignant = infiltrative, invasive
What are the common cellular features in malignant neoplasms
- High nucleus:cytoplasm ratio due to enlarged nucleus with more DNA taking up the cytoplasmic space
- Nuclear pleomorphism (varied shapes)
- Necrosis
- High and abnormal mitotic rate
What is metastasis
Secondary growth of a neoplasm at one or more locations, away from the primary site - this only occurs with malignant neoplasms
How can metastasis occur
Spread via
- lymphatics
- blood vessels
- across mesothelial-lined cavities
- through CSF
Outline the general mechanism of invasion and metastasis
- Detachment of tumour cells
- Attachment to ECM via specific receptors
- Degradation of ECM via collagenases and proteases
- Locomotion through ECM via motility factors
- Vascular intravasation
- Interaction of tumour cells with host lymphatics
- Formation of tumour embolus
- Adhesion to endothelium at distant site
- Vascular extravasation
- Regrowth of metastatic clone
Where do carcinomas metastasise
Early = via lymphatics to the lymph nodes Late = via bloodstream to lungs and liver
Where do sarcomas metastasise
lung
Where do bone metastasis occur
prostate, lung, thyroid, kidney, breast = 5 most common metastatic sites
Where does bronchial carcinoma metastasise
adrenal glands
What symptoms do neoplasms cause
- Anaemia
2. Cachexia = weightless, anorexia, fever, weakness
Why do neoplasms cause anaemia
- haemorrhage from the neoplasm
- decreased life span of erythrocytes
- replacement of bone marrow by metastatic tumour
- autoantibodies against RBCs
Why do neoplasms cause cachexia
Results from cytokines secreted by the tumour or reactive host cells which have an effect on systemic responses - the underlying metabolic changes are obscure
Why does cancer cause death
- spread to multiple organs
- metastasis at vital sites e.g. arteries causing blockage
- immunosuppression thus from opportunistic infections
- organ failure
- haemorrhage
- late second malignancies
