Carcinogenesis Flashcards
Define hyperplasias
The increase in the number of cells in an organ or tissue
Define metaplasia
The replacement of one differentiated somatic cell with another differentiated somatic cell type in the same tissue
Define dysplasia
The presence of abnormal cells within a tissue or organ.
Define neoplasia
- neoplastic transformations due to multiple genetic and epigenetic alterations in the cells
- autonomic uncontrolled cell growth
- development of new but useless tissue that variables stimulates the tissue of origin
- new clones of neoplastic cells with new biological characteristics evolve new mutations and epigenetic events
- benign or malignant.
Explain neoplastic transformation.
- Autonomic uncontrolled cell growth.
- development of new but useless tissue that variably stimulates the tissue un origin
- new clones ui neoplastic cells with new biological features evolve following new mutations and epigenetic events,
Factors that affect tumour incidence
Increased age, gender, geographic factors, genetic factors, immune suppression, environmental factors, multifactorial
Discuss the significance or the parenchyma of a tumour
Transformed neoplastic cells, determines the biological potential of one tumour und one function and the name of the tumour
Discuss the significance of the stroma ur a tumuur
The supportive connective tissue and blood vessels which are critical for tumour growth, tumour cells induce angiogenic and other growth factors
The stroma enables transport of nutrients to neoplastic cells, intercellular signalling
Describe tumour angiogenesis.
The neoplastic transformation of a single cell which results in the growth of a tumour. Growth limited by the ability u nutrients to diffuse into it. Angiogenic factors are produced which stimulates proliferation and in growth of blood vessels which enables tumour growth to be supported by perfusion.
Tumour eventually outgrows the blood supply and central neurosis occurs.
Describe the sessile pattern of neoplasia
Flat and usually goes unnoticed
Describe the polyploid
Generally localised without invasion of adjacent tissue there fore generally benign
Describe the behaviour ulcerated, fungating and annular
Destructive invasive;malignant
Example of ulcerated tumour
Peptic ulcers in the stomach
Example of annular tumour
Tb of the small bowel
What tumour shapes are usually benign
Sessile, pedunculated polyp and papillary
What tumour shapes are usually malignant
Fungating, ulcerated & annular
By what features do neoplasms differ histologically from their corresponding tissue
- Reduction of differentiation including function of the malignant cells
- Reduction of cellular cohesion
- Nuclear enlargement, pleomorphism and hyperchomasia
- Increased mitotic activity
What are the must severe changes associated with malignancy
Anapiasia.
Define anaplasia
The loss of structural and functional differentiation of normal cells
What is the function of anaplasia
No or abnormal, inappropriate function.
Cytology of anaplasia (6)
I. Pleomorphism
2. High nuclear: cytoplasmic
3. Large nucleoli
4. Abnormal mitoses
s. Hyperchromatic nuclei
6. Loss of cellular cunesion.
How are tumours classified
According to their behaviour and histogenesis
What are the 3 biological behaviours of tumours
Benign, malignant and uncertain.
Histogenesis
- Stimulates the cell of origin
1. Morphological differentiation
2. Functional differentiation.
Why ist one precise classification of tumours important
For planning effective treatment.
Characteristics of benign tumours.
-Grow slowly
- exophytic growth
- well differentiated
- cytology mimics benign cells
- localised and non invasive
- ulceration, necrosis rare
- no metastases
- usually not fatal
Characteristics of malignant tumours.
- rapid growth
- endophytic
- less differentiation
- cytology malignant to anaplastic
- invasive and destructive ; poorly circumscribed
- ulceration, necrosis common
- metastases often
- often fatal
Can hormones stimulate the growth of tumours
Yes. Hormones can stimulate proliferation on neoplastic cells
What influence can the reduction of vascular perfusion have on a benign tumour
Ischaemia and necrosis can follow
Why are benign tumours usually well circumscribed
Capsule - easy to remove. Destructive infiltration is absent in benign tumours.
In what 5 ways may benign tumours cause clinical problems
- Pressure on adjacent tissue.
- Obstruction to flow of fluid
- Production of a hormone
- Transformation into a malignant neoplasm
- Anxiety
Define a lipoma
A benign tumour of fat with well-circumscribed margins
Define a neurofibroma
Benign tumour or peripheral nerve with well-circumscribed margins
Define a fibroadenoma
Benign tumour of the breast with men circumscribed margins
Define an intraduct papilloma
A benign tumour on the breast with a stalk and well-circumscribed margins without invasion
6 Characteristics of malignant tumours
- Invasive and destructive
- Rapid growth rate- correlates with growth rate
- Metastasise
- Normal effect on neoplastic cells
- Vascular impairment
- Immunity-tumour regression occurs.
Provide 3 ways as to how malignant tumours show local destructive infiltration.
- Invade adjacent structures
- Ulcerations/ necrosis/ bleeding
- Obstruction,
Perineural invasion
Tumour grows along the nerve.
What is a sarcoma
A malignant connective tissue tumour that is poorly circumscribed
- destructive invasion of adjacent skeletal muscle.
Provide 7 ways us to now malignant tumours may cause clinical problems
- Pressure on and destruction de adjacent tissue
- Secondary tumour formation
- Blood loss from ulcerated surfaces
- Obstruction of flow
- Production of a hormone
- Other paraneoplastic effects causing weight loss and debility
- Anxiety and pain
What is histogenetic classification
Classification by cell or tissue of origin
What determines one tumour grade or degree of differentiation
The extent To which the tumour resembles histologically and or functionally its cell or tissue of origin
Differentiation of benign tumours
Well differentiated
Differentiation on lipoma
Tumour cells appear like Normal fat cells
Differentiation of liver cell adenoma
Mimics normal liver with bile production, but without purtul truss
Differentiation of Adenomas of endocrine glands
Well differentiated morphologically and functionally
Differentiation of malignant tumours
Variable grade of differentiation
Tumour grading
Well, moderate, pour or as defined according to specific criteria for a particular tumour type
3 differentiations that are indicative of biological aggression
Cytological, architectural and functional
Liposarcoma differentiation
Tumour cells mimic lipoblasts with large, hyperchromatic pleomorphic nuclei and irregular sized fat globules with scalloping of nuclei
Describe the functional differentiation of melanoma
Melanin pigment production by tumour cells. Malignant neoplasm of melanocytes
Benign epithelial tumours
Papillomas or adenomas
Malignant epithelial tumours
Carcinomas
Malignant connective tissue tumours
Sarcomas
Smooth muscle tumour
Leiomyoma (benign) and leiomyosarcoma (malignant)
Striated muscle
Rhabdomyoma, rhabdomyosarcoma
Adipose tissue
Lipoma, liposarcoma
Blood vessels
Angioma, angiosarcoma
Bone
Osteoma, osteosarcoma
Cartilage
Chondroma, chondrosarcoma
Mesothelium
Benign mesothelioma , malignant mesothelioma
Synovium
Synovioma, synovial sarcoma
Carcinoma
Malignant neoplasia of epithelial origin
Squamous epithelium
Squamous carcinoma
Glandular epithelium
Adenocarcinoma
Glandular epithelium with papillary growth pattern
Papillary adenocarcinama
Glandular epithelium with cystic grunt butters
Cystadenocarcinoma
Carcinoma in situ
Malignant epithelial neoplasm confined to the epithelial layer from which it derives- precursor lesion may be present ( intro epithelial neoplasia or dysplasia)
In area around tumour, not invaded yet
Difference between screening and diagnostic test
Screening → no symptoms
Diagnostic test → symptoms
How is the stage of a tumour determined
By looking at the size, The lymph nodes and metastasis , invasion of adjacent organs
Benign tumours of mesenchyme
- Oma
Malignant tumours of mesenchyne
Sarcomas
Burkitt lymphoma
Malignant tumour- a B cell lymphoma associated with ebb and malaria and endemic in certain parts of Africa
Ewing sarcoma
A tumour of bone of uncertain histogenesis
Hodgkin lymphoma
A lymphoma characterised by the presence of Reed sternberg cans
Kaposi sarcoma
Derived from vascular endothelium and associated with aid s and human herpes virus 8 infection
A malignant tumour of lymphoid tissue
Lymphoma
Malignant tumour of melanaytes
Melanoma
Malignant tumour of mesothelium
Mesothelioma
Malignant tumour of bone marrow
Leukemia
A teratoma
A neoplasm of germ cell origin that forms cells representing all 3 germ cell layers of the embryo. Organoid arrangement of tissue
Totipotential stem cell
Potentially any type of tissue/cell
Mature teratoma
Skin, hair, thyroid, bruin tissue, bronchus
Immature teratoma
Contains variable mixture of immature and mature tissues
Mixed germ cell tumour
Immature teratuma with one or more other malignant germ cell components
Blastoma
Malignant tumours stimulating the embryological appearance of the organ in which it occurs
Nephroblastoma
Malignant tumour in young children <5 - kidney
Retinoblastoma
Malignant tumour- eye - children <5
Neuroblastoma
In the adrenal medulla or nerve ganglia- may mature into benign ganglioneurama
Hepatablastoma
Liver
Mixed tumours
Non-organoid combinations of mature tissue types of I germ cell layer e.g. Pleomorphic adenoma
Mesenchymal elements
Epithelial elements
Pleomorphic adenuma
Benign, well circumscribed . Mixed chondromyxoid and duct and myoepithelial cells in a non-organoid pattern
Where do Endocrine tumours derive from
- Diffuse endocrine system ( hormone secreting epithelial cells)
- neuronal or paraneuronal cells
Examples of endocrine tumours
Medullary carcinoma, beta-cell tumuur, adrenal paragangliomas
Carcinoid
Now used mainly for serotonin producing neuroendocrine tumour especially in the git or lung - produces no other peptides
Polyp
Any macroscopic projection above an epithelial surface. May bec neoplastic or non neoplastic
Hamartoma
A tumour like lesion that is not neoplastic.
The growth is coordinated with the individual and it lacks the autonomy of a true neoplasm.
Always benign and usually consist of two or more mature cell types normally found in the organ in which the lesion Arises
Pulmonary harmatoma
Lobules of cartilage with entrapped respiratory epithelium and often ever mesenchymal tissues such us fat, smooth muscle , myxoid stroma
Cysts
Epithelium lined, fluid filled structure or space
Parasitic cyst
Non neoplastic, hydatid due to echinococcus granulosus
Congenital cyst
Due to embryological defects-branchial cyst
Retention cyst
Mucous cyst in oral cavity
Implantation cyst
Due Tu traumatic implantation
Neoplastic cyst examples
Cystic teratoma , cystadenoma, cystadenocarcinoma.
How do neoplastic cells show self-sufficiency in Growth signalling
They are relatively or absolutely autonomous, unresponsive to extracellular growth control
