Neoplasia Flashcards
Tumour definition
Mass or swelling
Neoplasm
Abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the change
Define benign
Neoplasm which is localised and cannot spread
Define malignant
Neoplasm which can invade and destroy adjacent structures and spread to distant sites
Define cancer
Malignant neoplasm
Define metastasis
Spread of a cancer to a distant site
What is the normal cell turnover and healing and repair
The cells proliferate to replace damaged or apoptotic cells
And once the tissue has regained its normal structure proliferation ceases - no mutations have occurred
What is a clinically irrelevant mutation
By chance a cell may develop a mutation which does not confer a survival advantage
So proliferated but the irrelevant mutation does not dominate since they have no survival advantage over the normal cells
What happens in a benign neoplasia
A neoplasm is formed by the clinal expansion of a single precursor cell that has a survival advantage over its neighbours
In the pretumoural stageneoplastic mutations are present in the tissue, but have not yet given rise to a tumour. These are typically clinically silent
Over time the neoplastic clone dominates the tissue and forms a mass. Cells do not have malignant capacity so is a benign tumour
Where do benign tumour go
Nowhere they are limited to the site of origin, but show expansive growth and do not metastasise Often clinically irrelevant but Can cause Compression Obstruction Bleeding Hormone secretion Cosmetic effect Progression to malignancy
What is in situ neoplasia
Some mutations (arising either de novo or in benign neoplasm) give cells malignant capacity The malignant phenotype comes to dominate the tissue , but so far the cells have not actually invaded the basement membranes So is in situ malignancy
Where does in situ neoplasia go
Biologically has malignant potential , but has not yet invaded beyond the confines of the normal tissue e.g. Basement membrane
Can be considered pre cancerous
Complete excision is curative
Often asymptomatic as does not form a mass
Important for screening programmes
Cancer is
Cells with a malignant phenotype that invade local structures and spread through tissues
Invasive malignancy
What is cancer
Malignant neoplasm
Has the ability to invade and destroy
Capacity to invade and destroy adjacent tissues
Has the capacity to metastasise
Metastasis invade and destroy adjacent tissue
Hallmarks of cancer
Sustaining proliferative potential Evading growth suppressors Avoiding immune destruction Enabling replicative immortality Tumour promoting inflammation Activating invasion and metastasis Inducing angiogenesis Genome instability and mutation Resisting cell death Deregulating cellular energetics Sustaining proliferative signalling
Where are the most likely met sites
Lymph nodes from lymph vessel spread
Blood vessels to liver, bone marrow, brain, lung, kidney and adrenal
Pathogenesis of cancer
Genetics and environmental factors
Genetics role in cance r
Inherited cancer syndromes - Li Fraumeni
Familial cancers - higher frequency in some families without a clearly defined pattern of transmission
Environmental factors role in cancer
UV rays Ionising radiation Viruses Tissue inflammation Occupational exposure Carcinogens
Clinical effects of cancer
Compression
Obstruction
Bleeding
Local destruction of tissues
Paraneoplastic syndromes
- hormone mediated Cushing said due to ACTH like substance released in lung cancer
- immunologically mediated - lambert Easton syndrome- caused by antibodies against presynaptic voltage gated calcium channels at the NMJ causing severe muscle weakness
Cachexia TNF produced by peritumoural macrophages and some tumour cells mobilises fat from tissue and suppresses appetite
Pain
Death
What types of histopathology are submitted
Cytology - a fluid sample of tumour looking for cells
Biopsy - solid sample of tumour - cells
Excision - surgical removal of the whole tumour
Types of examination of the histopathology sample submitted
Macroscopic examination
Microscopic examination
Special tests - immunohistochemistry FISH PCR
Role of the histopathologist in managing neoplasia
Provide a diagnosis - benign/ in situ/ malignant - classification Provide prognostic info - tumour grade, vascular invasion, perineural invasion, extent of invasion, tumour stage Provide predictive info - testing the neoplasm for markers of responsiveness to specific therapies Screening
Benign macroscopic shapes
Sessile
Pedunculated
Papillary
Malignant macroscopic shapes
Fungating
Ulcerated
Annular
Microscopic features of benign neoplasms
Resemblance to normal tissue Circumscribed tumour border No invasion Often no hyperchromasia Regular nuclear border No pleomorphism No prominent nucleoli Low mitotic activity
Malignant neoplasms microscopic features
Poor resemblance to normal tissue Poorly defined tissue border Invasion Hyperchromasia Irregular nuclear border Pleomorphism Prominent nucleoli High mitotic activity
Factors involved in classification
Behaviour and site Benign or malignant And where Cell of origin Epithelia Mesenchymal
Classification terminology
Suffix oma
Malignant epithelial original carcincoma
Malignant mesenchymal origin sarcoma
What are the pathological prognostic features
Tumour invasiveness
- depth of invasion, vascular invasion, perinueural invasion
Grade
- degree of histological resemblance to parent tissue
Stage
- extent of anatomical spread
Depth of invasion of a malignant melanoma
Breslows depth
Imp prognostically
Grade defined by
Adenocarcinoma
Gleasons pattern
Less like original more poor prognosis
Gleason score
Sum of two commonest Gleason patterns on the tumour imp progonsis in prostatic adenocarcinoma
What does tumour grade categorise by
Extent of the invasion
What does TNM stand for
T tumour size and extent of local invasion
N degree of spread to regional lymph nodes
M presence or absence of distant mets
Prefix p means done by a pathologist rather than clinically or radiological
Other staging system in colorectal
Dukes staging
Types of predictive tests
Immunohistochemistry for hormone receptors in breast cancer
FISH fluorescence in situ hybridisation for gene rearrangemt in lung cancer
PCR based methods for mutations in colorectal cancer
Screening basis
Concept of detecting carcinoma in situ
Before it is invasive
Pathologists are involved in programmes for cervical, breast and colorectal cancers
