Using the pathologist Flashcards

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1
Q

Define neoplasia 3

A
  • uncontrolled cell proliferation
  • proliferation continues in absence of inciting cause
  • neoplastic cells originate from single cell which has lost ability to control its division
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2
Q

What is tumour classification based on?

A

clinical and pathological features

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3
Q

What are gross features of benign tumours

A
growth by expansion
low to moderate growth rate
tumour well demarcated (compresses surrounding tissue)
smooth in gross outline
surrounding CT capsule
freely mobile on palpation
homogenous cut surface (cystic in glandular tissue)
little haemorrhage or necrosis
surgical removal often easy
no recurrence if completely excised
no metastasis
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4
Q

What are microscopic features of benign tumours?

A

very similar to tissue of origin
well organised
benign endocrine tumours can be functional
surrounding CT capsule - tumour doesn’t broach this
few or no mitoses
generally no haemorrhage or necrosis

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5
Q

Gross features - malignant tumours

A

growth by invasion
not encapsulated
not usually mobile on palpation
complete removal often difficult
often recurs after excision
often ulcerate if on skin or mucosal surface
secondary changes - internal necrosis and haemorrhage
can metastasise to local LNs and lungs (often)

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6
Q

Microscopic features - malignant tumours

A
pleomorphism
anisokaryosis
increased nuclear: cytoplasmic ratio
prominent nucleoli
normal/abnormall mitoses
loss of cohesiveness and structure
syncytia
secondary changes - necrosis, fibrosis, inflammation
usually not encapsulated
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7
Q

Define anisokaryosis

A

variable size and shape of nucleoli

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8
Q

Define pleomorphism

A

variable cell size and shape

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9
Q

Define papilloma

A

benign, surface epithelia

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10
Q

Define adenoma

A

Benign tumour, glandular epithelia

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11
Q

Define thyroid adenoma

A

glandular epithelia (benign) tumour prefixed by the tissue of origin

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12
Q

Define carcinoma

A

malignant, epithelial origin

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13
Q

Define adenocarcinoma

A

malignant tumour of glandular epithelia

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14
Q

Is a tumour ending in -oma benign or malignant?

A

Benign (except granuloma - chronic inflammation). Tumours with the ending -sarcoma are malignant

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15
Q

Define lymphoma

A

tumours of lymphoid system

usually malignant

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16
Q

Define melanoma

A

Tumour of melanocytes

some benign, other malignant (malignant melanomas)

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17
Q

Define MCT (mastocytoma)

A

tumour of mast cells

vary in degree of malignancy

18
Q

Define leukaemia

A

tumours derived from cells of BM which then circulate in the blood

19
Q

Define teratoma

A

germ cell tumours with elements of ectoderm, endoderm and mesoderm

20
Q

Define sarcoid. Cause?

A

low grade fibrosarcoma

commonly seen in the skin of horses (caused by BPV)

21
Q

How can tumours metastasise? 4

A

lymphatic
vascular
trans-cavity
local

22
Q

What is lymphatic spread typical of?

A

Carcinomas

Tumour spreads across serosal surfaces (may be associated with effusions)

23
Q

Outline vascular spread

A

Typical of sarcoma

Tumour seeds widely to internal organs (liver and lungs)

24
Q

Outline trans-cavity spread

A

Typical of mesothelioma
Less common
Spreads across serosal surfaces

25
Q

Outline local metastasis

A

May occur in multiple tumour types
Less common
Spread along fascial planes

26
Q

Define multicentric tumour

A

where it is difficult to determine a primary site as multiple tumours are present at first presentation

27
Q

List some malignant tumours that metastasise rapidly and constantly

A
tonsillar carcinomas
pancreatic carcinomas
OSA
oral and digital melanomas
mammary carcinomas (cats)
28
Q

List some malignant tumours that metastasise slowly or rarely

A
SCC = tend to invade extensively before undergoing metastasis
Fibrosarcomas = tend to invade and therefore recur at the site of excision, without undergoing metastasis
29
Q

List 4 examples of IHC markers and their uses

epithelial, mesenchymal, TC and BC markers

A

Cytokeratin - epithelial marker - carcinoma
Vimentin - mesenchymal marker - sarcoma
CD3 - TC marker - TC lymphoma
CD79a - BC marker - BC lymphoma

30
Q

What is tumour grading?

A

measure of differentiation

31
Q

How can tumours be graded? 4

A

Light microscopy (SCC - keratin production)
Immunophenotyping (lymphoma)
Detection of genetic mutations (lymphoma)
Use of proliferation markers (MCTs)

32
Q

What is cytogenetics?

A

A method of tumour grading where the specific mutation is detected - this is the standard practice for human lymphomas.

33
Q

What is Ki-67?

A

A proliferation marker that can be detected for tumour grading. Particularly useful for MCT grading in dogs.

34
Q

Define clinical audit

A

to determine why a therapy might have failed

35
Q

How can a pathologist help a clinician

A
Obtain definitive Dx or shortlist
Prognosis estimate
Treatment plan
Client education
Clinical audit
36
Q

What should a biopsy report contain? 5

A

Signalment and clinical history
Gross description
Clear and concise histological description
Diagnosis or likely DDx
Comments on biological behaviour and prognosis with recommendations for monitoring/treatment and client education.

37
Q

When should you call the path lab? 4

A

If path diagnosis doesn’t fit with clinical findings
Before tissue collection in unusual cases
Urgent results needed
Follow-up appreciated

38
Q

What does the pathologist require?

A

Representative sample
Correctly submitted
Full clinical history

39
Q

How can a sample be taken?

A

Incisional - punch, trucut, endoscopic or wedge#
OR
Excisional

Include margin of normal tissue
Avoid necrotic and cavitated areas (usually central, except bone tumours where area of max lysis is useful)
Mark margins of interest (suture tag or indelible dye)
Identify samples from different sites
[Imaging guidance]

40
Q

How do you submit a sample?

A

Large volume of neutral buffered formalin (4:1 or 10:1)
<2cm in longest dimension
Larger specimens unfixed if close to lab
Royal Mail guidelines for path. specimens
Label - indelible, practice, owner, animal, site, difference between sites, normal and abnormal sites (esp skin biopsies)

41
Q

What should be included on the full clinical history?

A
Signalment
Clinical History
Previous lab results
previous therapy
Clinical Dx or DDx
Special considerations (forensic, legal)
Gross description/photo