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Flashcards in Using the pathologist Deck (41):
1

Define neoplasia 3

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

2

What is tumour classification based on?

clinical and pathological features

3

What are gross features of benign tumours

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

4

What are microscopic features of benign tumours?

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

5

Gross features - malignant tumours

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)

6

Microscopic features - malignant tumours

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

7

Define anisokaryosis

variable size and shape of nucleoli

8

Define pleomorphism

variable cell size and shape

9

Define papilloma

benign, surface epithelia

10

Define adenoma

Benign tumour, glandular epithelia

11

Define thyroid adenoma

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

12

Define carcinoma

malignant, epithelial origin

13

Define adenocarcinoma

malignant tumour of glandular epithelia

14

Is a tumour ending in -oma benign or malignant?

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

15

Define lymphoma

tumours of lymphoid system
usually malignant

16

Define melanoma

Tumour of melanocytes
some benign, other malignant (malignant melanomas)

17

Define MCT (mastocytoma)

tumour of mast cells
vary in degree of malignancy

18

Define leukaemia

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

19

Define teratoma

germ cell tumours with elements of ectoderm, endoderm and mesoderm

20

Define sarcoid. Cause?

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

21

How can tumours metastasise? 4

lymphatic
vascular
trans-cavity
local

22

What is lymphatic spread typical of?

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

23

Outline vascular spread

Typical of sarcoma
Tumour seeds widely to internal organs (liver and lungs)

24

Outline trans-cavity spread

Typical of mesothelioma
Less common
Spreads across serosal surfaces

25

Outline local metastasis

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

26

Define multicentric tumour

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

27

List some malignant tumours that metastasise rapidly and constantly

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

28

List some malignant tumours that metastasise slowly or rarely

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

29

List 4 examples of IHC markers and their uses
(epithelial, mesenchymal, TC and BC markers)

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

30

What is tumour grading?

measure of differentiation

31

How can tumours be graded? 4

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

32

What is cytogenetics?

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

33

What is Ki-67?

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

34

Define clinical audit

to determine why a therapy might have failed

35

How can a pathologist help a clinician

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

36

What should a biopsy report contain? 5

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

When should you call the path lab? 4

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

38

What does the pathologist require?

Representative sample
Correctly submitted
Full clinical history

39

How can a sample be taken?

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

How do you submit a sample?

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

What should be included on the full clinical history?

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

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