MCT, Skin and Bone Tumors

Question 1

Where do Mast cell tumors originate?

Answer 1

Bone marrow

Question 2

Where do MCT mature?

Answer 2

Tissues

Question 3

What do the Mast cell granules contain?

Answer 3

Histamine, heparin, tissue degrading proteases

Question 4

What are the classic signs of inflammation?

Answer 4

Swelling, heat, redness, pain

Question 5

What enzyme is mutated that leads to Mast Cell Tumor formation?

Answer 5

C-kit (tyrosine kinase)

Question 6

T/F: MCT is the most common skin tumors in dogs

Answer 6

True

Question 7

What are some breeds that are predisposed to MCT?

Answer 7

Boxer, Vizsla, Boston Terrier, Shar-Pei, Dutch Pug

Question 8

Where are some common areas on the body to find MCT?

Answer 8

Trunk/perineal region, limbs, head/neck

Question 9

What signs are associated with histamine?

Answer 9

GI - vomiting, anorexia
Hives, pruritis
Wheezing
Hypotension

Question 10

What would you see in cytology for MCT?

Answer 10

Round, discrete cell tumors

Large round cells with purple granules

Question 11

What are some ways to stage a MCT?

Answer 11

Aspiration of lymph nodes*

U/D of abdomen, bone marrow aspirate

Question 12

T/F: Thoracic rads and buffy coats are diagnostic staging tools for cutaneous MCT

Answer 12

False. MCT does not spread to the lungs and the buffy boat has false positives

Question 13

T/F: Even palpably normal lymph nodes can have metastasis

Answer 13

True

Question 14

What are the metastatic potentials in relation to the grades of the MCT?

Answer 14

Low grade - <10%
Middle grade - <15%
High grade - 90%

Question 15

What are the factors observed when histologically grading MCT?

Answer 15

Location, architecture, morphography, edema/necrosis

Question 16

What should you premedicate a patient with MCT with before surgical excision of the tumor?

Answer 16

diphenhydramine

Question 17

T/F: Wide surgical excisions are required for MCT surgery

Answer 17

True

Question 18

How large are the excisions for MCT surgery?

Answer 18

2-3 cm margins, 1 fascial plane deep

Question 19

T/F: Inking of the tumor is always recommended

Answer 19

True

Question 20

When would you perform radiation therapy on a patient with MCT?

Answer 20

Post-op, if the margins were not possible to completely remove

Question 21

Is it possible to just give RT alone as treatment?

Answer 21

Yes, but it’s not as good as surgery

Question 22

When would you perform chemotherapy on patients with MCT?

Answer 22

As a palliative treatment for non-resectable tumors and as an adjuvant for aggressive MCT

Question 23

What are some chemo drugs that work against MCT?

Answer 23

Prednisone, CCNU, vinblastine, chlorambucil, toceranib, masitinib

Question 24

What chemo drug directly works against tyrosine kinase, and thus c-kit?

Answer 24

Palladia (toceranib)

Question 25

What chemo drug would be used after local control of MCT?

Answer 25

Vinblastine, CCNU, Chlorambucil, Prednisone

Question 26

How can you treat histamine-induced gastic ulceration from MCT?

Answer 26

Diphenhydramine, famotidine, ranitidine, omeprazole, sucralfate

Question 27

T/F: Advanced/metastatic MCT means a much lower prognosis

Answer 27

True

Question 28

How should you treat a completely excised grade 1/2 MCT? Incomplete?

Answer 28

Complete - Monitor Incomplete - re-excise or RT

Question 29

How should you treat a completely excised grade 3 MCT? incomplete?

Answer 29

Complete - chemotherapy Incomplete - radiation/chemotherapy

Question 30

T/F: Feline MCT is associated with FeLV and FIV

Answer 30

False

Question 31

Which form of feline MCT is most commonly seen?

Answer 31

Mastocytic form

Question 32

Which form of feline MCT is seen in siamese cats?

Answer 32

Histiocytic form

Question 33

T/F: Compact Mastocytic MCTs are usually more malignant

Answer 33

False. Diffuse is more metastatic

Question 34

T/F: Histiocytic MCTs are benign

Answer 34

True

Question 35

Where do you normally find mastocytic, compact MCT?

Answer 35

Head and neck

Question 36

T/F: Multiple compact MCT on a feline is a sign of poorer prognosis

Answer 36

False. Not correlated with degree of malignancy or metastasis

Question 37

How should you treat diffuse miliary cutaneous MCTs?

Answer 37

Chemotherapy, symptomatic (histamine)

Question 38

T/F: Cats have splenic MCTs more commonly than dogs

Answer 38

True

Question 39

How do you determine the prognosis of splenic MCTs?

Answer 39

Lymph node metastasis

Question 40

How would you splenic MCTs?

Answer 40

Surgery and chemotherapy

Question 41

T/F: Intestinal MCTs metastasize frequently.

Answer 41

True

Question 42

How should you treat intestinal MCTs?

Answer 42

Remove the tumor with surgery

Question 43

Where do soft tissue sarcomas arise from?

Answer 43

Embryonic mesoderm - connective tissue

Question 44

What might be some possible causes of STS?

Answer 44

Breed predisposition, vaccine/microchip injection sites

Question 45

How do you diagnose STS?

Answer 45

FNA/cytology

Question 46

What are the most common sites of metastasis for STS?

Answer 46

lungs, liver, lymph nodes

Question 47

How would you test for staging of STS?

Answer 47

Diagnostic imaging

Question 48

How should you treat a vaccine associated sarcoma?

Answer 48

2 cm marginal resection

Question 49

What is the most common primary bone tumor in dogs?

Answer 49

Osteosarcoma

Question 50

What type of animal usually gets osteosarcoma?

Answer 50

Older and larger

Question 51

What is the rule with tumor location on the limbs?

Answer 51

Towards the knee away from the elbow

Question 52

What are some fractures that may lead to osteosarcoma?

Answer 52

metallic implants, chronic osteomyelitis, exposure to ionizing radiation

Question 53

T/F: Osteosarcomas commonly cross the joints and invade the neighboring bone

Answer 53

False

Question 54

T/F: Metastasis is very common with osteosarcoma

Answer 54

True

Question 55

How does osteosarcoma metastasize?

Answer 55

Through the blood/bone marrow

Question 56

Where does OSA usually metastasize to?

Answer 56

Lungs

Question 57

What are some major signs of OSA?

Answer 57

Lame, PAIN, swelling

Question 58

How can you diagnose OSA?

Answer 58

FNA/cytology for most cases

Question 59

Is ALP staining for OSA useful?

Answer 59

Yes

Question 60

What is the best choice of treatment for localized OSA?

Answer 60

Surgery

Question 61

When is it possible to spare the limb with surgery?

Answer 61

If the primary tumor is <50% of the bone and <360` around the tissues

Question 62

T/F: Dogs typically die from the pain with OSA

Answer 62

False. Systemic disease associated with OSA

Question 63

What are some chemotherapy options to treat OSA?

Answer 63

Carboplatin, doxorubicin, combination chemo, low dose continuous chemo