Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

3. Cat & Dog > oncology 3 > Flashcards

oncology 3 Flashcards

1
Q

Describe & discuss the different methods of diagnosis for mast cell tumours (MCT)
- which is usually best? how can we tell what we are looking at? what possible negative effect?

A
  • FNA
    > cytology usually diagnostic
    >characteristic appearance - mononuclear, granules
    => graulation varies (often with grade)
    => stain can affect ability to see granules
    >may produce inflammatory reaction, bleeding after aspiration
    => “Darier’s sign” due to degranulation, release of contents such as heparin, histamine
    => Premedication with diphenhydramine (Benadryl) if concerned
    ()
  • incisional biopsy
  • excisional biopsy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what stain for MCT?

A

wright-giemsa is good
- diff-quick not great

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

MCT incidence and signalment

A

– 7‐21% of all skin tumours
– 11‐27% of all malignant tumours
()
mean age = 9 years
– BUT there is a WIDE AGE RANGE
()
- many breeds predisposed: Boxer, Boston, Lab, pug, golden…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

MCT - canine, location

A
  • Cutaneous and subcutaneous most common
  • 50% trunk
  • 40% extremity
  • 10% head and neck
  • visceral - metastatic
    > spleen, liver, kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

MCT clinical signs

A

Mass
* solid skin mass
> may ulcerate, swell, or be pruritic
* Lipoma‐like
* Subcutaneous
* Mucosal (oral)
()
Paraneoplastic effects
- edema, shock
- GI signs
- bleeding tendencies
- ulceration, wound dehiscence
- pruritis

** systemic illness common with metastatis disease**

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

contents of mast cells

A
  • Histamine
  • Heparin
  • Eosinophilic chemotactic factor
  • Proteolytic enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

MCT Location, Appearance, Clinical Signs

A
  • most frequently dermal or subcutaneous
  • most solitary
  • usually raised, may be ulcerated
  • may be solid, soft (like lipoma), mucosal (e.g. oral)
  • may have been present for long period of time
  • no specific signs, but pruritis, GI ulceration possible, bleeds
    > Systemic illness common with metastatic disease
  • CAN LOOK LIKE ANYTHING
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

clinical staging of MCT - how do we do it?

A
  • diagnosis: FNA ± biopsy (for histology grading)
    ()
    Staging:
    – CBC & biochemical profile
    – Cytology of draining LN
    – Abdominal ultrasound + cytology
    ()
    – ± Bone marrow
    – ± Coagulogram (PT, PTT, FDP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

cancer stage vs grade

A
  • a grade describes the appearance of cancer cells and tissue
  • a stage explains how large the primary tumor is and how far the cancer has spread in the patient’s body.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does it mean if we find mast cells in the liver, spleen, or lymph nodes when trying to stage the MCT?

A
  • presence of mast cells in the liver or spleen does NOT equal metastatic mast cell tumour
  • LN shouldn’t have large numbers of mast
    cells in a normal population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

use of CT for MCT staging, etc.

A
  • useful for staging abdomen on large dog
  • useful to evaluate lymph node
  • useful to plan surgery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the stages for a mast cell tumor and what do they mean?

A
  • Staging (modified from WHO)
    > Stage I: single skin tumour
    > Stage II: single skin tumour + regional lymph node (LN)
    > stage III: multiple skin tumours or single large deep tumour ± regional LNs
    >Stage IV: distant spread (blood or bone marrow)
    ()
    > a: without systemic signs
    > b: with systemic signs
  • Prognosis worse with increasing stage
  • Multiple tumours may not have a worse prognosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

are multiple MCT common? related to one another? how should we approach the 2nd tumour?

A
  • 20-25% of dogs with a MCT will get a 2nd MCT during their lifetime
  • unrelated to 1st MCT
  • likely predisposition
  • needs to be treated like a new primary and not as a metastatic site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

MCT diagnostic / staging steps - how do we decide what to do next?

A
  1. Anatomic site amenable to wide surgical excision?
    > if yes…
  2. negative prognostic factors present?
    > if no…
  3. excise with wide surgical margins. submit for grade and margin
    > if complete margins, intermediate or low grade, and no negative prognostic indicators
  4. routine follow-up
    ()()()
    - if not amenable to wide surgical excision
    OR
    - if negative prognostic factors present
    OR
    - if poorly differentiated, highly proliferative, or surgical margins incomplete…
    > Expand diagnostics prior to definitive therapy:
  5. biopsy for histologic grade (+/- KIT analysis)
  6. lymph node aspirate
  7. abdominal US +/- spleen/liver aspirate
  8. CBC, biochem
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how do we answer: how bad is it? for MCT

A
  • diagnosis: FNA
  • biopsy for histo grading
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

MCT prognosis requires:

A
  • histologic grade
  • stage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Patniak groups for MCT grade: what are they and what criteria is considered? what are most of them?

A

3 groups:
> low (I): well differentiated
> intermediate (II)
> high (III): poorly differentiated
()()
Based on:
* Mitotic figures
* Differentiation
* nuclear pleomorphism
> multinucleated cells, bizare nucleu, karyomegaly
* depth?
()()
vast majority will get a grade II
> ‘high vs low’ grade II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Kiupel 2 tier system: high grade vs low grade MCT prognisis

A
  • High Grade associated with a significantly shorter time to metastasis and survival time
    > low grade > 2 years
    > high grade < 4 months
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

markers of proliferation other than mitotic index? what is a negative prognostic factor for MCT?

A
  • the higher the marker the worse the tumor
    > AgNORs
    > Ki-67
    > PCNA
    > Doubling time
    ()
    -rapid tumor growth and sudden appearance negative prognostic facotr
20
Q

mutation in what gene affects MCT prognosis? what does it do?

A

c-kit
> encondes KIT, a tyrosine kinase receptor that binds stem cell factor, promoting the development/ function of mast cells

21
Q

canine MCT prognosis overall depends on:

A
  • grade
  • extent (clinical stage)
  • tumour location
    > subungual, oral, mucous membranes mucocutaneous jct worse
    > preputial, scotal worse
    > SC better prognosis
  • breed
    > boxer less aggressive disease
  • growth rate
  • proliferation indices
    > MI, AGNORs, PCNA, Ki-67
  • recurrence
  • systemic signs
  • c-kit mutation
22
Q

prognostic factors for canine dermal MCT

A
  • systemic signs
  • growth rate
  • grade
  • mitotic index
  • proliferation markers
  • c-kit mutation
  • surgical margin
  • extent (stage)
  • breed
  • tumor location
23
Q

prognostic factors for canine subcutaneous MCT

A
  • grading system for cutaneous not valid for these
  • aggressiveness based on mitotic index
    > many act benign
24
Q

can you grade a MCT form cytology?

A

Bottom line with cytology:
If it looks bad, it probably is‐‐‐
If it doesn’t look bad, it still might be

25
Q

what is considered a ‘biologically high grade MCT’?

A
  • High grade
  • low grade but with a positive lymph node
  • Muco‐cutaneous localisation
26
Q

are all MCT similar?

A

Not one of them
is like the other
don’t ask me why,
please ask your mother.

27
Q

MCT treatment modality chosen depends on?

A
  • Based on clinical stage & histo grade
    – this doesn’t mean we necessary do a biopsy
    every time!
    – often treat based on a presumptive grade
    > behaviour and cytology
28
Q

mainstay of treatment for MCT?

A
  • surgery
29
Q

surgery for MCT - recommendations are based on what type of MCT?
- what type of excision? how do we do it?

A
  • recommendations & grading based on cutaneous MCT
  • mainstay of treatment for MCT
  • well differentiated & intermediate
    > wide surgical excision
    > early better
    => “proportional margins” (> 5 mm & < 3 cm) + clean fascial plane deep
    => clean margins
    => surgical cure
30
Q

MCT surgery indications / reasons to perform

A
  1. curative excision
  2. cytoreduction (“debulking”)
  3. palliation
31
Q

guidelines for MCT surgery
- margins? considerations?

A
  • always know your local anatomy and fascial planes
    > If you are unsure of either of these, mass is likely in a location that needs advanced imaging
  • for masses < 1cm, often 1 cm margin enough … but need to consider the behaviour and anticipated grade
  • for masses >1cm, often 2 cm enough but need to consider behaviour
  • we don’t know for sure the most appropraite margin for grade 3
    ()
  • biopsy if it will be challenging to get 2 cm margins and close primarily > important to know if grade 3 in these cases
  • clip wide
  • be prepared for a big hole - have a plan!
  • remember 3cm margins + 1 cm mass = ~10cm scar
  • consider the consequences if dirty margins
32
Q

MCT surgical challenges

A
  • poorly defined masses
  • Poor local healing
    > histamine release
  • Determination of deep margin
33
Q

MCT excision - dirty margins? now what?

A

reexcision or radiation therapy

34
Q

MCT indications for radiation therapy - why we do it

A
  • loco-regional control
    – alone or in combination with surgery and/or chemotherapy
  • curative vs palliative
35
Q

types of radioation therapy for MCT

A
  1. local vs systemic
  2. palliative vs curative
36
Q

how does radiation for MCT work?

A
  • In principle:
    – radiation destroys cells
    – primary target is DNA
    – indirect effect by destruction of tumour vasculature
    – usually, cells have to divide in order to die
37
Q

MCT treatments, ranked:

A
  1. wide surgical excision
  2. radiation (50-75% CR)
  3. chemotherapy
    > poor 3rd choice compared to local therapy
38
Q

chemotherapy (systemic) MCT indications

A
  • metastasis
  • high grade
  • non-surgical
  • microscopic without access to radiation therapy
  • muco‐cutaneous location
39
Q

MCT chemotherapy treatment drugs

A
  • glucocorticoids
  • vinblastine
  • lomustine (CCNU)
  • toceranib (Palladia®)
40
Q

MCT targetted therapy

A

tyrosine kinase inhibiitor (TKI)
- we want to stop:
> KIT is a tyrsine kinase receptor that binds stem cell factor, promotes development and function of mast cells

41
Q

ancilliary therapies for MCT? types and their purpose

A
  • used in MCT to combat the effects of histamine
  • H2 antagonsits
    > famotidine, ranitidine
  • omeprazole
  • sucralfate
  • +/- misoprostol
  • H1 antagonists
    > diphenhydramine
42
Q

how does stelfonta (tigilanol tiglate) work? what is it for?

A

– injection for non‐metastatic MCT in dogs
– Licensed in USA not yet in Canada
- destroys tumours inducing rapid hemorrhagic necrosis

43
Q

treatment approach for stage 0 or 1, grade I or II canine MCT

A
  1. surgical excision if poss (wide margins, complete)
    > follow up
    ()
  2. If wide surgical excision not possible:
    Ideal: cytoreductive surgery and adjuvant radiation therapy
    Alternate:
    - cytoreduction followed by medical therapy
    - radiation therapy alone (ossible surgery to follow)
    - medical therapy alone (possible surgery to follow)
    - amputation
    ()
  3. if surgical margins not complete:
    - Options:
  4. reexcise with wider margins
  5. adjuvant radiation therapy
  6. adjuvant medical therapy
    > then follow up
44
Q

treatment approach for high grade biologically aggressive canine MCT

A
  1. wide surgical excision if possible
    > assess margins and confirm grade
    > if complete margins…
    > adjuvant medical therapy +/- regional node irradiation
    > follow up
    ()
  2. if wide excision not possible
    - Options:
    Ideal:
  3. cytoreductive surgery
  4. adjuvant radiation therapy +/- regional lymph node
  5. adjuvant medical therapy
    Alternatives:
  6. cytoreduction followed by medical therapy
  7. medical therapy alone
  8. radiation therapy and medical therapy
    ()
    - if surgical excision attempted but margins not complete, options:
  9. reexcision with wider margins
  10. adjuvant radiation therapy to primary site +/- regional node
    > then adjuvant medical therapy +/- regional node irradiation
45
Q

what type of masses make us suspicious of MCT?

A

all dermal/subcutaneous masses

46
Q

are feline and canine MCT similar?

A

they are different

3. Cat & Dog (33 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions