Lecture 10 - The Pathology of Cancer: Classifications of Neoplasms Flashcards
Why is an understanding of cancer pathology important?
- Explains how cancers present clinically
2. Histopathological assessment importmnt for: diagnosis, prognosis and treatment
What is the definition of neoplasia?
A neoplasm is a mass of cells that:
- have undergone an irrerversible change from normality
- proliferate in an uncoordinated manner
- are partially or completely independent of the factors which control normal cell growth
In what four ways can neoplasms be classified?
- behaviour
- histogenesis
- histological
- functional
Malignant neoplasms have the capacity for:
1.
2.
- local invasion into surrounding tissue
2. spread to distant sites to form secondary deposits. Metastases occur via lymph of homogenous
What does staging tell us?
extend of spread (local or distant)
Describe the generic TNM system for staging
T = tumour N = nodes M = metastasis
Where do most malignant neoplasms originate from?
Where do most benign neoplasms originate from?
epithelia
mesenchymal tissues
Give 2 examples of haemato-lymphoid neoplasms
Give 2 examples of germ cell neoplasms
lymphoma, leukaemia
teratomas, seminoma
What is differentiation?
Differentiation is the degree to which a neoplasm histologically resembles its tissue of origin
e.g benign neoplasms = always well differentiated
malignant neoplasms = differentiation variable
What is grading?
Describe grade 1, 2 and 3
Grading is a term used to describe the degree of differentiation
1 = well differentiated
2 = moderately differentiated
3 = poorly differentiated
Grading has implications for …
prognosis and treatment
e.g. well-differentiated prostate cancer can be managed conservatively
Some malignant tumours are so poorly differentiated the tis is impossible to determine their histogenesis. These are called ……
anaplastic neoplasms
Classification of common neoplasms table
see lecture
What are the three histological subtypes of thyroid carcinoma?
Why are cancers classified in this way?
papillary
follicular
anaplastic
Differnt behaviour and prognosis according to histological subtype
Describe functional classification?
- classification according to substances produced
- endocrine neoplasms secreting secreting functionally active hormones e.g. insulinoma, prolactinoma
What are teratomas?
Where can they occur?
neoplasms derived from embryonic germ cells
have the capacity to form representatievves of all 3 germ cell layers
- ovaries - usually benign
- testes - usually malignant
- midline structures - behaviour variable
In what 5 ways can benign and malignant be compared?
- essential differences
- gross appearance
- microscopic features
- growth characteristics
- effects on host
In what 5 ways can benign and malignant be compared?
- essential differences
- gross appearance
- microscopic features
- growth characteristics
- effects on host
What are the essential differences between benign and malignant neoplasms?
invasion –> malignant
metastates –> malignant
What aspects of gross appearance can be compared?
shape - well circumsized vs irregular Size - generally smaller vs generally larger Haemorrhage - unusual vs common Ulceration - unusual vs common Necrosis - unusual vs common
What aspects of microscopic features can be compared?
nuclear size - normal vs enlarged nucleoli - small/inconspicuous vs prominent pleomorphism - absent vs often marked mitoses - infrequent vs frequent (may be atypical) differentiation - good vs variable
What is pleomorphism?
tissue arrangement and loss of polarity
What are uterine leimyomas often known by?
Are they benign or malignant?
uterine fibroids
benign
well circumscribed/well differentiated
How can they be compared in terms of growth characteristics?
speed
- slow vs rapid
spontaneuous arrest
- common vs rare
How can the effects of host be compared?
mechanical pressure
- yes vs yes
invasion
- no vs yes (may damage vital structures)
metastasis
- no vs yes (common cause of death)
paraneoplastic syndromes
- no vs yes (neurological, haematological, endocrine, immunological
death
- very uncommon vs frequent (if untreated)
