Neoplasm Classification Flashcards
Define neoplasm
Mass of cells which have undergone an irreversible change from normality, causing them to proliferate in an uncoordinated manner and are partially or completely independent of the factors which control normal cell growth
Tumours can be classified according to … factors
Behavioural
Histogenic
Histological
Functional
Behavioural classification
Benign or malignant
Determined by the capacity of the tumour invade the surrounding tissue
Spread to distant sites to form secondary deposits (metastases) - occurs via 2 main routes lymphatic and haematogenous
Cancer is used to describe
All types of malignant neoplasm
What is the extent of the spread described by
Staging Common staging system: TNM system Tumour Nodes Metastasis Specific staging systems - dukes in colon cancer
What is staging important for
Prognosis
This determines therapeutic options - local resection versus chemo/radio
Difficult distinction benign / malignant
Some have an intermediate manner - basal cell carcinoma of skin - invade local tissues, but doesn’t metastasise
Histogenic classifies neoplasms according to ?
the tissue of origin - epithelial or mesenchymal
What is the term differentiation used to describe?
Used to describe the degree to which a neoplasm histologically resembles its tissue of origin
In benign tumours is the degree of differentiation a lot or a little
A lot
Malignant what is the degree of differentiation
Variable
Term grading is used to describe
The degree of differentiation e.g.
1 = well differentiated
2= moderately differentiated
3= poorly differentiated
What does the tumours grade have implications for?
Prognosis and treatment
Well differentiated may be managed conservatively
Some malignant tumours are so poorly different tested it is impossible to determine their histogenesis - called anaplastic tumours
What are the two most important features used in classicising neoplasms
Behavioural and histogenesis
Some tumour types can be further classifies according to special … characteristics
Histological
E.g. Thyroid
Have histological subtypes which impacts the prognosis and route of spread
- papillary highest frequency route of spread is lymphatic (lymph node mets) and prognosis is very good
- follicular 10-20% frequency, spread route haematogenous (bone) good survival
- anaplastic <5% frequency, local invasion and poor survival
Some tumours classified according to a substance or substances produced. This is called
Functional classification
Applies particularly to endocrine tumours which secrete functionally active hormones
Such as pancreatic islet cell tumours
Pituitary tumours
What is a teratoma
Neoplasms derived from embryonic germ cells. Have the capacity to form all 3 germ cell layers - totipotent
Where do teratomas occur
Ovary - usually benign
Testis - usually malignant
Midline structures - behaviour variable
What are embryonic tumours
Arise from neoplastic transformation occurring in the developing organs
Derived from multi potent embryonic blast cells giving the suffix blastoma
Frequently have divergent differentiation - epithelial and mesenchymal
Majority present at or soon after birth
Most are highly malignant but may respond well to aggressive treatment
What are hamartomas
Not genuine neoplasms but tumour like malformations
Many present at birth and stop growing when the host stops growing unlike a neoplasm which continues to grow
Benign or malignant
Invade and metastasise
Malignant
Shape or benign
Well circumscribed
Shape malignant
Irregular
Which bigger benign or malignant
Usually malignant
Sometime benign can be huge too
Haemorrhage common in B or M
Malignant
Necrosis common in B or M
M
Ulceration common in B or M
M
Size of nucleus in benign
Normal
Size of nucleus in malignant
Larger
Nucleoli in benign and malignant
B- small/inconspicuous
M- prominent
Pleomorphism B or M
M
Mitoses m or b
Infrequent b
Frequent m
Differentiation in benign
Good
Differentiation in malignant
Variable
Growth in B and M
B - slow
M - fast
Spontaneous arrest ? B and M
B common
M rare
Classification of Breast lumps benign
Fibroadenoma Comment benign Mostly occur in <30 women Smooth Well circumscribed lump Highly mobile on palpation
Classification of breast lump malignant
Breast carcinoma Commonest malignant Commonest cause of death in women >50 Irregular Poorly circumscribed lumps Rarely mobile on palpation die to invasion
Caecum cancer/ascending colon
Often polyploid
Rarely cause bowel obstruction
Insidious presentation- anaemia, weight loss
Sigmoid colon
Often stenosing
Frequently cause bowel obstruction
Typically present with alteration in bowel habit
Types of specimens obtained for psychological assessment
Biopsies - small pieces of tissue Endoscopic biopsies (upper, lower GIT, bronchus) Needle biopsies (radiologically guided Punch biopsies (skin)
Cytology specimens - cells individual or groups Smears -cervical Endoscopic brushings Body fluids Fine needle aspiration specimens
Surgical resection specimens
Biopsies usually taken to
Confirm a diagnosis. Identify a malignancy and identify the histological type
Info gained can be used to plan further treatment
Surgical resection vs non surgical
Decisions relating to therapeutic options are frequently made in MDT
Limitations to biopsying tumours
Tumour heterogeneity - mixed pattern of differentiation
Targeting the lesion accurately
- small lesions
- inaccessible or potentially dangerous sites
- surrounding stromal tissue reaction
Cytology specimens are used to
Diagnose in a less invasive way
Bladder cancer
Fine needles much thinner than biopsy needles - may enable access to areas a biopsy needle can’t reach
Smaller tissue samples provided (individual cells or groups of cells rather than tissue cores)
Interpretation in biopsy may be more difficult due to larger tissue being obtained
Surgical resection specimens used to
Resection intended to be curative some cases palliative
Confirm diagnoses of malignancy
Determine the aggressiveness of a tumour -histological grade
Assess the extent of spread -histological stage
Examine completeness of excision
Used as a basis for determining further treatment
Grading of malignant neoplasms
Well differentiated - grade1
Moderately differentiated -grade2
Poorly differentiated (anaplastic) - grade3
Staging
Extent of spread
What are the 3 components of staging
Tumour - size or extent of spread of the primary lesion e.g. 1-4
Nodes - extent of spread to lymph nodes 0-3
Metastasis - presence or absence of distant metastasis 0 or 1
What are the stages e.g. Breast cancer
T1 - <2cm
T2- 2-5cm
T3 - >5cm
T4- any size with direct extension into chest wall and/or skin
Wharton is the stage system used for colorectal cancer
Dukes
What are the stages used in dukes
A - confined to submucosa/muscle
B - through muscle to serosa
C - lymph node involvement
D- distant metastasis
Macroscopic assessment of tumour resection specimens
Size
Shape(well circumscribed)
Extent of local spread
Proximity to surgical resection margins
Identification of lymph nodes (imp for staging)
Other macroscopic features where relevant - colour, haemorrhage, necrosis
Tumour resection assessment microscopic assessment
Confirms or establishes a diagnosis of cancer
Histological type - glandular, squamous
Degree of differentiation- histological grade
Frequency of mitoses
Local invasion
- presence important for determining malignancy
- extent important in staging
Vascular invasion
Examination of lymph nodes (for metastases)
Immunohistochemistry in tumour pathology is used for:
Establishing diagnosis of malignancy
Clonality in lymphoid neoplasms
- reactive (inflammatory) infiltrates have mixed population of cells
- neoplastic infiltrates have a ‘pure’ population of cells
Immunohistochemistry test for prognostic markers -types tested for
Markers of cell turnover
Determine high or low grade metastatic potential
What type of labelling is used to determine grading potential
Ki 67 labelling index
Immunihistichemisty can be used to determine
Prognosis and treatment factors
In tumours which are known to be malignant
How can it determine treatment options
Markers such as HER2 in breast cancer
Insitu hybridisation detected what
Recognise specific RNA and DNA sequences in tissue sections
