Tumour Pathology Flashcards

1
Q

What is a tumour?

A

• Neoplasm-“Newgrowth”
• Usuallyonecelltypewithsupporting
tissue structures
– Neoplastic cells
– Stroma (connective tissue, fibroblasts, blood vessels, immune cells)
• Autonomous
– Response to physiological stimuli lost or abnormal, allowing unregulated growth

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2
Q

What are the hallmarks of cancer?

A
Self sufficiency in growth signals 
Evading apoptosis 
Insensitivity to anti-growth signals 
Tissue invasion and metastasis 
Limitless replicative potential 
Sustained angiogenesis
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3
Q

What are the possible results form a cancer diagnosis/excision

A

Must be predicted:

CURE
RELAPSE
METASTASIS
DEATH

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4
Q

What is a benign tumour?

A
  • Well circumscribed
  • Slow growth
  • No necrosis
  • Non-invasive
  • No metastasis
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5
Q

What is a malignant tumour?

A
  • Poorly circumscribed
  • Rapid growth
  • Often necrotic
  • Invasive
  • Metastasis
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6
Q

What is the difference between benign and malignant tumours?

A
Benign
• Well circumscribed
• Slow growth
• No necrosis
• Non-invasive
• No metastasis
Malignant 
• Poorly circumscribed 
• Rapid growth
• Often necrotic 
• Invasive
• Metastasis
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7
Q

What is the clinical relevance of benign and malignant tumours?

A

• Benign tumour (not always clinically benign)
– Does not invade surrounding structures
– Does not metastasise

• Malignant tumour
– Invades
– Metastasises
– Can kill

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8
Q

What are the clinical effects of benign tumours?

A
• Do not invade or metastasise
• Not always clinically benign! 
– Space occupying effects
• Obstruction
• Epilepsy
• Conduction abnormalities
– Haemorrhage 
• Pulmonary
• Gastrointestinal 
– Hormone production
• Pituitary
• Adrenal
• Endocrine pancreas
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9
Q

How do malignant tumours spread?

A
  • Directly invade locally (‘cancer the crab’)
  • Via the lymphatics
  • Via the bloodstream (haematological)
  • Through body cavities (transcoelomic)
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10
Q

What specific set of rules and patterns do all tumours follow when metastasising?

A
None 
• Tumour cells don’t all behave the same
• Not all tumours metastasise in the same manner/ with the same distribution
– Prostate -> bone
– Lung -> brain, adrenals
– Breast -> lung, liver, bone, brain 
– Ovary -> peritoneal cavity
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11
Q

What are the macroscopic features of benign tumours?

A

Intact surface
Exophytic growth
Homogenous cut surface
Circumscribed or encapsulated edge

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12
Q

What are the macroscopic features of malignant tumours?

A
Heterogenous cut surface due to necrosis 
Ulcerated surface 
Endophytic growth 
Vascular permeation 
Irregular infiltrative edge
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13
Q

What are the microscopic features of benign tumours?

A
  • Resemble tissue of origin
  • Well circumscribed
  • Well differentiated
  • Minimal nuclear pleomorphism
  • Mitotic figures normal
  • No necrosis
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14
Q

What are the microscopic features of malignant tumours?

A
  • Variable resemblance
  • Poorly circumscribed
  • Variable differentiation
  • Variable pleomorphism may be anaplastic
  • Mitotic figures abnormal
  • Necrotic
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15
Q

What are the cytological features of malignancy?

A
  • High nucleo-cytoplasmic ratio
  • Nuclear hyperchromasia
  • Nuclear pleomorphism
  • Abnormal chromatin structure
  • Abnormal mitotic figures
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16
Q

Discuss factors considered in Histological (Histogenetic) Classification - Grade of tumour

A
  • Resemblance to tissue of origin-differentiation
  • Degree of resemblance to tissue of origin allows GRADING - Determined histologically
  • Grade correlates broadly with clinical behaviour
  • Precise classification important for planning treatment
17
Q

What does the stage of a cancer refer to?

A

Classification of spread

18
Q

What is Dukes’ Staging System for Colorectal Cancer?

A
  • A - confined to bowel wall
  • B - through bowel wall but no lymph node involvement
  • C - lymph nodes involved
  • D - distant spread
19
Q

What is the nomenclature associated with cancer?

A
  • All end in – oma
  • Benign epithelial tumours are either papillomas or adenomas
  • Benign connective tissue tumours begin with term denoting cell of origin e.g. lipoma
  • Malignant epithelial tumours are carcinomas
  • Malignant connective tissue tumours are sarcomas
20
Q

What is used to define major tumour categories?

A
  • Epithelial origin
  • Connective tissue origin (mesenchymal)
  • Lymphoid/haematopoetic origin
21
Q

What are the different types of epithelial tumours?

A

• Benign
– Papilloma (squamous, transitional)
– Adenoma

• Malignant
– Squamous cell carcinoma
– Transitional cell carcinoma
– Adenocarcinoma

• May be associated with a non-invasive precursor
– Carcinoma in situ
– Intraepithelial neoplasia

22
Q

What are the different types of mesenchymal tumours?

A

• Benign
– Lipoma
– Haemangioma etc

• Malignant
– Liposarcoma
– Haemangiosarcoma etc

• Not usually associated with a non-invasive precursor

23
Q

Name some miscellaneous tumours

A
  • Melanoma
  • Lymphoma
  • Teratoma
  • Embryonal tumours(‘blastomas’)
  • Carcinoid tumours
  • Cysts
24
Q

What is a teratoma?

A
  • Contains elements of all three embryonic germ cell layers
  • Of germ cell origin
  • Benign and malignant forms
  • Ovarian–almost always benign
  • Testicular–more often malignant
25
Q

What are all the factors you should remember when identifying tumours?

A
Incidence
Age
Sex
Geographical distribution
Predisposing factors
Macroscopic features
Microscopic features
Spread
Prognosis
26
Q
In
A
Surgeon's 
Gown
Physicians 
May
Make
Some
Progress
A
Incidence
Age
Sex
Geographical distribution
Predisposing factors
Macroscopic features
Microscopic features
Spread
Prognosis
27
Q

Discuss tumour genes coded for by X chromosomes

A
• Enzyme marker
• Lyon inactivation hypothesis
• Only one X chromosome in
female cells is active.
• One X chromosome is randomly switched off
28
Q

How do tumour genes coded for by X chromosomes show that tumours have a clonal origin?

A

The normal tissue is a 50 : 50 mixture of both enzyme markers

If the tumour arises from a single
cell i.e. is clonal in origin, then all the Tumour cells will have the same enzyme marker

29
Q

Do all tumour cells reproduce?

A

No probably not:

Basal cell carcinomas
Squamous cell carcinomas (head & neck) - effectively treated with radiation
From size can calculate the number of tumour cells
From radiation data can calculate how many cells are killed
PROBLEM
exceeds the number capable of being killed by radiation
number of cells in the tumour VASTLY
CONCLUSION either the calculations are wrong (unlikely) OR
only 1 in 103 – 104 cells can repopulate the tumour