Oncology I

Question 1

what to know about cancers?

Answer 1

they are common, fatal, & difficult to treat

Question 2

How many dogs die of cancer?

Answer 2

1 in 4

Question 3

Can you tell cancer type or prognosis from feeling or looking at a mass?

Answer 3

No

Question 4

What 3 things do we wonder about a mass?

Answer 4

1. Diagnosis - what is it?
2. Staging - how far has it gone?
3. Treatment - what to do w/ it?

Question 5

What are ways we diagnose a mass?

Answer 5

1. FNA
2. Biopsy
3. bone marrow sampling
4. clonality test
5. flow cytometry

Question 6

what diagnostics do we start w/ and why?

Answer 6

FNA
- quick, minimally invasive method for obtaining cellular samples from masses, LNs, or internal organs.

Question 7

What size needle do we use for an FNA?

Answer 7

22-25G w/ or w/o a syringe

Question 8

How is an FNA performed?

Answer 8

insert a needle into the mass, redirect it multiple times, & then expel the material onto a slide

Question 9

Why should we give Benadryl before sampling a potential mast cell tumor?

Answer 9

because a mast cell tumor will release histamines

Question 10

Why do we sometimes use ultrasound for FNAs?

Answer 10

because it can guide us to actual tumor tissue & not necrotic tissue

Question 11

What do we look for on FNA cytology?

Answer 11

1. are there nucleated cells?
2. is the population uniform?
3. what type of cells are they?
4. malignancy criteria

Question 12

What 3 types of cells are there on FNA?

Answer 12

epithelial, mesenchymal, & round

Question 13

What types of cells are these?

Answer 13

epithelial

Question 14

what is a feature of epithelial cells?

Answer 14

they stick together well

Question 15

What kind of cells are these?

Answer 15

mesenchymal

Question 16

What kind of cells are these?

Answer 16

round

Question 17

cell type?

Answer 17

Mesenchymal

Question 18

cell type?

Answer 18

epithelial

Question 19

cell type?

Answer 19

round

Question 20

What are ddx for round cell tumors?

Answer 20

lymphoma, mast cell tumor, histiocytic sarcoma, hystiocytoma, plasma cell tumor, melanoma, transmissible venereal tumor (TVT)

Question 21

punch biopsy vs FNA?

Answer 21

FNA looks at cell morphology while w/ punch biopsy you can look at actual tissue structure
- need tissue architecture to confirm if it is benign or malignant

Question 22

Type of biopsy?

Answer 22

Tru-cut
- uses a bigger needle than FNA
- it is long enough to sample deeper tissues
- works well in tumors that will bleed like crazy if punched

Question 23

Answer 23

punch
- works well for superficial or skin tumors

Question 24

Type of biopsy?

Answer 24

wedge
- when you cant safely do a punch
- small sample taken w/o complete removal
- used for larger tumors

Question 25

Type of biopsy?

Answer 25

excisional - when the mass is really small - may end up taking entire visible tumor - complete removal of the mass w/ minimal margins - used especially when excision can be both dx & therapeutic

Question 26

Questions to ask when trying to decide if you should biopsy

Answer 26

1. what are my ddx? 2. will the result change my case management? - will you excise anyway? - will you treat it differently (excise, chemo, amputation)?

Question 27

Important parts of the histopathology report:

Answer 27

1. dx (histologic type, benign vs malignant) 2. grade, mitotic count (# of cells in mitosis when the pathologist counts them -> more dividing, more likely to be an aggressive cancer) 3. margins (determines if excision was complete) 4. other tumor specific factors: necrosis, differentiation, inflammation, atypia, etc.

Question 28

What if the histo does not fit w/ the clinical picture?

Answer 28

- ask for a second opinion - not uncommon to have a clinical decision change w/ this

Question 29

What can immunohistochemistry tell us?

Answer 29

1. diagnostic confirmation 2. prognosis

Question 30

What will you see on bloodwork w/ cancers that do not form a mass & what should be done?

Answer 30

on bloodwork: - unexplained cytopenia or increased cell count - circulating atypical cells - monoclonal gammopathy (presence of excessive amounts of myeloma protein or monoclonal gamma globulin in the blood) Should do bone marrow testing

Question 31

What do you need for bone marrow sampling?

Answer 31

- sedation / GA - sternal - 22 G needle

Question 32

Where do we sample for bone marrow?

Answer 32

- 1st sternal bone, iliac crest, proximal humerus, & femur

Question 33

what are commonly diagnosed cancers with bone marrow aspirate/biopsy?

Answer 33

lymphoma, leukemia, multiple myeloma, myeloproliferative neoplasia, myelodysplastic syndrome

Question 34

What are two additional tests to tell neoplastic from reactive lymphocytes?

Answer 34

- PCR for Antigen Receptor Rearrangement - flow cytometry for lymphocytes

Question 35

What is the purpose of PARR?

Answer 35

- distinguishes lymphocytic neoplasia from reactive lymphocytes

Question 36

What is the principle of PARR?

Answer 36

detects rearrangements in B-cell (Ig genes) & T-cell (TCR genes) receptors from any samples that contain genomic DNA

Question 37

Findings of PARR?

Answer 37

clonal expansion suggests lymphoma/leukemia, immunophenotyping

Question 38

What is the purpose of flow cytometry?

Answer 38

differentiation btwn reactive lymphocyte populations, phenotypic characterization of lymphocytic cancers

Question 39

What is the procedure of flow cytometry?

Answer 39

fresh cells from blood, LN, or bone marrow are labelled w/ fluorescent antibodies for cell surface markers (CD3, CD4, CD5, CD8) & analyzed

Question 40

Findings of flow cytometry?

Answer 40

clonal expansion suggests lymphoma/leukemia, immunophenotyping