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Lecture title - Neoplasia: tumour classification and behaviour

92 important questions on Lecture title - Neoplasia: tumour classification and behaviour

What are the two types of tumours according to behavioural classification?

Benign and malignant

What is a benign tumour?

A non-invasive, local tumour with slow growth rate and close histological resemblance to parent cell

What is a malignant tumour?

An invasive and metastasizing/spreading tumour with relatively rapid growth rate and variable histological resemblance to parent cell

What is a non-necessary characteristic of a tumour to be considered malignant?

A tumour can still be considered malignant even it doesn't metastasize as long as it has other features of a malignant tumour.

What are the common shapes of benign tumours?

Sessile, pedunculated polyp, papillary
(growing away from skin/surface)

What are the common shapes of malignant tumours?

Exophytic/fungating, ulcerated, annular (growing into the skin)

What is histogenetic classification tumours based on?

Classified by cell of origin and histologically determined

What is histological grade of tumours?

The degree of resemblance that the tumour cell has to parent tissue, which correlates to clinical behaviour

What are the major categories of tumour cell origin?

Epithelial cells, connective tissue, lymphoid cells, haematopoietic cells

Discuss the degree of differentiation in benign tumours

Usually well differentiated to closely resemble the parent tissue

Discuss the degree of differentiation in malignant tumours

Ranges from well differentiated (close morphological resemblance) to undifferentiated (anaplasia)

Compare the histological differences in adenocarcinoma of the colon that is well differentiated and poorly differentiated

Well differentiated adenocarcinoma of the colon = glandular structures similar to normal mucosa
Poorly differentiated adenocarcinoma of the colon = more solid growth pattern, little gland formation

What are the morphological changes that follow lack or differentiation or anaplasia?

1. Pleomorphism: variation in size and shape of cells
2. Abnormal nuclear morphology: hyperchromatic (dark staining), increased nucleus to cytoplasm ratio (ex: 1 to 4, 1 to 6 instead of 1 to 1)
3. Increased and atypical mitosis
4. Loss of polarity: disruption of normal cell orientation

Compare the growth rate of benign and malignant tumour

Benign - slow growth rate
Malignant - relatively rapid growth rate

Compare mitosis of benign and malignant tumours

Benign - infrequent mitosis
Malignant - frequent and atypical mitosis

Compare the degree of histological resemblance of benign and malignant tumours to normal tissue

Benign - good histological resemblance to normal tissue
Malignant - variable and often poor histological resemblance to normal tissue

Compare the nuclear morphology of benign and malignant tumours

Benign - almost normal nuclear morphology
Malignant - usually enlarged, hyperchromatic, irregular outline, multiple nucleoli, and pleomorphic (variation in size and shape) nucleus

Compare the ability to invade in benign and malignant tumours

Benign - can't invade
Malignant - can invade

Compare the potential of metastases in benign and malignant tumours

Benign - never
Malignant - frequent metastases

Compare the characteristics of borders of benign and malignant tumours

Benign - often circumscribed (restricted) or encapsulated border
Malignant - often poorly defined or irregular border

Compare the accompaniment of necrosis following a benign and malignant tumour

Benign - necrosis is rare
Malignant - necrosis is common

Compare the occurrence of ulceration in benign and malignant tumours

Benign - ulceration is rare
Malignant - ulceration is common on skin or mucosal surfaces

Compare the direction of growth on skin or mucosal surfaces for benign and malignant tumours

Benign - often exophytic (away from surface)
Malignant - often endophytic (into the surface)

What nomenclature do tumours usually end in?

- oma
(ex: adenoma, sarcoma, papilloma)

What is the nomenclature of benign tumours in epithelial cells dependent on?

Origin, architecture, and patterns

What is the general nomenclature of a benign tumour of connective tissue?

Prefix denoting cell of origin + OMA

What is the nomenclature of a malignant tumour of epithelial cells?

Carcinoma

What is the nomenclature of a malignant tumour in connective tissue?

Prefix denoting cell of origin + SARCOMA

Give the name of each the benign and malignant tumour of squamous cells (epithelial)

Benign --> squamous cell papilloma
Malignant --> squamous cell carcinoma

Give the name of each the benign and malignant tumour of transitional cells (epithelial)

Benign --> transitional cell papilloma
Malignant --> transitional cell carcinoma

Give the name of each the benign and malignant tumour of basal cells (epithelial)

Benign --> basal cell papilloma
Malignant --> basal cell carcinoma

Give the name of each the benign and malignant tumour of glandular cells (epithelial)

Benign --> adenoma
Malignant --> adenocarcinoma

Give the name of each the benign and malignant tumour of smooth muscle (mesenchymal)

Benign --> leiomyoma
Malignant --> leiomyosarcoma

Give the name of each the benign and malignant tumour of striated muscle (mesenchymal)

Benign --> rhabdomyoma
Malignant --> rhabomyosarcoma

Give the name of each the benign and malignant tumour of adipose tissue (mesenchymal)

Benign --> lipoma
Malignant --> liposarcoma

Give the name of each the benign and malignant tumour of blood vessels (mesenchymal)

Benign --> angioma
Malignant --> angiosarcoma

Give the name of each the benign and malignant tumour of bone (mesenchymal)

Benign --> osteoma
Malignant ---> osteosarcoma

Give the name of each the benign and malignant tumour of cartilage (mesenchymal)

Benign --> chondroma
Malignant --> chondrosarcoma

Give the name of each the benign and malignant tumour of mesothelium (mesenchymal)

Benign --> chondroma
Malignant --> malignant mesothelioma

Give the name of each the benign and malignant tumour of synovium (mesenchymal)

Benign --> synovioma
Malignant --> synovial sarcoma

What are eponymously named tumours?

Tumours named after the person who first described or recognised the lesion, which doesn't indicate the origin or behaviour of the tumour

What is the character of teratomas in ovaries?

Benign and cystic

What is the character of teratomas in testes?

Malignant and solid

What are blastomas (embryonal tumours)?

Childhood malignancies that occur mainly in children under 5 years of age.

What types of cells are usually found in a hamartoma?

Two or more mature cell types normally found in the organ where the lesion arises.

List the 4 stages of typical malignant tumour growth

1. Malignant changes in target cell (non-lethal genetic damage/mutations)
2. Growth of transformed cells
3. Local invasion
4. Distant metastases

How do tumour cells become heterogenous?

Tumour cells become heterogeneous because the original genetically unstable transformed cell divides, accumulating new mutations. These mutations create different subclones, and variants with survival or growth advantages are selected and expand, producing a mixed population of tumour cells with different properties.

What allows tumour invasion?

abnormal cell motility, reduced cell–cell cohesion, and production of proteolytic enzymes that degrade extracellular matrix

What are the stages in the evolution of an invasive squamous cell carcinoma?

1. Normal epithelium = normally stratified squamous epithelium
2. Dysplasia = some loss of stratification
3. Carcinoma in situ = total loss of stratification, basement membrane intact
4. Invasion = erosion of basement membrane, access to blood vessels and lymphatics
5. Metastasis

Why is breaching the basement membrane crucial in metastasis?

Tumour cells cannot access blood vessels or lymphatics for metastasis until the basement membrane is breached.

What are the four main pathways of tumour spread/metastasis?

Local invasion, lymphatic spread, vascular spread, and trans-coelomic spread

What is meant by local invasion in cancer?

Tumour cells infiltrate, destroy, and replace surrounding tissues near the primary site.

What is lymphatic spread?

Spread via lymphatic drainage from the primary tumour

What is vascular spread?

Spread through blood vessels draining the primary site

What is trans-coelomic spread?

Spread of tumour across body cavities

What are the common sites for metastases?

Liver, lung, brain, bone

How do carcinomas and sarcomas differ in spread pattern?

Carcinomas prefer lymphatic spread; sarcomas prefer vascular spread.

Which cancer characteristically spreads to vertebrae?

Prostate carcinoma

What is meant by cell immortalisation in tumour cells?

Increased mitosis and reduced apoptosis, leading to uncontrolled growth.

How is cell immortalisation seen histologically?

Changes in nuclear size and nuclear staining.

What metabolic abnormalities may tumour cells show?

Production of foetal substances and unexpected hormones.

What are tumour markers?

Measurable substances in body fluids that aid diagnosis and monitoring of cancer.

What features define an ideal tumour marker?

Present in early developmental stage of tumour
Specific for malignant disease
Level of marker proportional to tumour burden (size and number of tumour cells)
Level of marker responsive to successful treatment (decreasing marker levels as tumour dies)

What does an asymptomatic patient with rising level of tumour marker after surgical removal of that tumour indicate?

Recurrence

What tumour types is alpha-fetoprotein used to monitor?

Liver cell cancer, non-seminomatous germ cell tumours of testis

What tumour types is carcinoembryonic antigen used to monitor?

Carcinomas of the colon, pancreas, lung, stomach, and heart

What is the marker of prostate cancer?

Prostate-specific antigen and prostate-specific membrane antigen

What are the local clinical effects of tumours?

Compression, invasion, ulceration, destruction of adjacent structures

What are the clinical metabolic effects of tumours?

Secretion of appropriate or unexpected products
Weight loss

What is paraneoplastic syndrome?

A rare complex of symptoms in tumour-bearing patients that isn't caused by direct tumour growth or spread

What is the psychological effect of tumours?

Patient anxiety

About what proportion of malignant cancer patients develop paraneoplastic syndromes?

10%

What factors influence the prognosis (medical prediction of likely course and outcome) of a tumour?

Tumour type, characteristics, grade, and stage
Available treatment options and their efficacy.

Compare tumour grade and stage

Tumour grade = degree of differentiation
Tumour stage = extent of spread

What is the purpose of tumour grading?

To determine the aggressiveness of level of malignancy

Which histological features are used to grade malignant tumours?

Mitotic activity, degree of differentiation, and nuclear pleomorphism

How are malignant tumours graded?

1. grades 1, 2, 3 (1=most like normal, 3=very different from normal)
2. well, moderately, or poorly differentiated

What does tumour grading correlate with?

Prognosis (higher grade = worse prognosis)

What does tumour staging describe?

The extent of local, regional, and distant spread

What is the clinical purpose of tumour staging?

Guides management and prognosis

What is tumour staging based on?

Size of the primary tumour, lymph node involvement, and presence or absence of metastases.

What does T1 to T4 indicate?

T1 (smaller tumour size)
T2
T3
T4 (larger tumour size)

What does N0 to N3 indicate?

N0 = no lymph node involvement
N1
N2
N3 (increasing number of lymph node involvement)

What does M0 to M2 indicate?

M0 = no metastases
M1
M2 (increasing number of metastases)

What does T2 N1 M0 describe?

A primary tumour that has is moderate in size (T2), has spread to few nearby lymph nodes (N1), and hasn't metastasized (M0)

Explain colorectal cancer using T1-T4.

T1: invades submucosa
T2: invades into muscularis propria but not through it
T3: spreads through muscularis propria
T4: invades adjacent organs

What does the “p” in pT1 mean?

That the stage "T1" has been identified by pathological examination of specimen

What type of features of malignancy are present in 'carcinoma in situ'?

Morphological features of malignancy, but not behavioural features

What features of carcinoma does the epithelial tissues of 'carcinoma in situ' show?

Cytological and histological features of carcinoma

How does increasing cancer stage relate to survival?

Higher stage is associated with lower five-year survival.

What is the importance of early cancer detection?

To find the cancers at curable stages

Why is the overall population benefits of cancer screening lower than individual benefits?

1. Earlier detection = prolongs survival time BUT doesn't change outcome
2. Screening more likely to detect better prognosis tumours
3. Diagnosis of harmless lesions from screening
4. Volunteers of screening more likely to have good than bad prognosis tumours
Overall, these inflate the number of cancers detected without actually reducing deaths

The question on the page originate from the summary of the following study material:

FM2004

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