Oncology - Mast Cell + Others

Question 1

What is a mast cell?

Answer 1

A bone marrow derived cell that lives in the periphery involved in allergic reactions

Question 2

True or False: MCTs are the most common skin tumor and malignant skin tumor.

Answer 2

True

Question 3

Where are MCTs most commonly located?

Answer 3

50% trunk and perineum
40% extremities
10% head and neck

Question 4

When is the mean age of diagnosis for MCTs?

Answer 4

8-9 years

Question 5

What are the clinical signs associated with MCTs due to?

Answer 5

the release of histamine and heparin

Question 6

What is Darier’s sign?

Answer 6

erythema and wheal formation at a MCT

Question 7

What clinical signs are associated with MCTs?

Answer 7

Bleeding when mass aspirated/excised
GI ulceration
Fever
Peripheral edema
Hypotensive events/collapse
Coagulation abnormalities

Question 8

What are the prognostic factors for MCTs?

Answer 8

Histologic grade, clinical stage, anatomic location, cell proliferation rate, growth rate, recurrence, systemic signs, breed, tumor size, and C-KIT mutation

Question 9

If MCTs are going to metastasize, where do they metastasize most commonly?

Answer 9

Regional lymph nodes
Systemic - distant lymph nodes, spleen, liver
Pulmonary (very rare)

Question 10

• Dogs with gross/visible MCTs are at increased risk of this systemic side effect due to the histamine present in their mast cells:
  a. Gastric ulceration
  b. epistaxis
  c. pulmonary metastasis
  d. uveitis

Answer 10

a. gastric ulceration

Question 11

What is the most common way to diagnose MCTs?

Answer 11

Fine-needle aspirate cytology +/-incisional biopsy

Question 12

How do you do a fine-needle aspirate cytology?

Answer 12

Use a 22G hypodermic needle and insert it into the mass for a minimum amount of 10 insertions. Then stain with Diff-Quik

Question 13

What cytological findings are consistent with a MCT?

Answer 13

Small to medium sized round cells

Abundant, small, uniform cytoplasmic granules that stain purplish-red

Question 14

What method should you NOT use to diagnose MCT?

Answer 14

excisional biopsy because it is very important to get margins on your first surgery

Question 15

What does the Patnaik system grade based on?

Answer 15

Cytoplasmic boundaries, nuclear shape/size, mitotic index, and granules

Question 16

Define grade I of the Patnaik system.

Answer 16

Well differentiated (10-20%)

Question 17

Define grade II of the Patnaik system.

Answer 17

Intermediate differentiated (60-80%)

Question 18

Define grade III of the Patnaik system.

Answer 18

Poorly differentiate/anaplastic with infiltrative growth (10%)

Question 19

What did the 2-tier grading scheme determine the survival time for a high grade MCT was?

Answer 19

less than 4 months

Question 20

What did the 2-tier grading scheme determine the survival time for a low grade MCT was?

Answer 20

greater than 2 years

Question 21

When should you consult a pathologist in MCT cases?

Answer 21

The histology does not = biologic behavior - rapidly growing, large tumor, and LN metastasis

Question 22

Why is palpation alone of the LN not recommended for MCT staging?

Answer 22

Because of the low sensitivity and specificity - normal LN size does not mean there is no metastasis

Question 23

How are 70-80% of MCTs managed?

Answer 23

With surgery alone

Question 24

How do you downstage large MCTs prior to surgery?

Answer 24

Chemotherapy, radiation therapy, and prednisone

Question 25

What surgical margins are recommended for cutaneous MCTs?

Answer 25

Lateral margins - 2 cm or maximal diameter of MCT, whichever is GREATER Deep margins - fascial

Question 26

What surgical margins are recommended for subcutaneous MCTs?

Answer 26

Lateral margins - 2cm or maximal diameter of MCT, whichever is LESS Deep margins - fascial layer

Question 27

What LN is most commonly excised in MCT patients?

Answer 27

the regional lymph node because they are often involved - recommendation is to excise it when possible

Question 28

True or False: Incomplete surgical excision followed by observation alone is correlated with a significant decrease in survival times in dogs and recurrence.

Answer 28

True

Question 29

In cases of incomplete surgical excision, what should you do?

Answer 29

Wide surgical excision or radiation therapy | Consider a MCT prognostic panel

Question 30

When is chemotherapy not indicated if there is incomplete surgical excision?

Answer 30

If it is a low grade MCT

Question 31

What are some prognostic panels for MCT?

Answer 31

Proliferation indicies, KIT staining patterns, and C-KIT mutation status

Question 32

When should you do KIT mutation testing?

Answer 32

In cases of a high/grade III/ high MI (metastatic index)

Question 33

What should you do if you get a positive KIT mutation result?

Answer 33

Chemotherapy + palladia

Question 34

What should you do if you get a negative KIT mutation result?

Answer 34

Chemotherapy alone vs. chemo and palladia

Question 35

When should you run a full MCT panel?

Answer 35

Incomplete resection Biologic behavior does not fit histopathology Hot anatomic sites (muzzles, mucocutaneous) Low owner risk tolerance

Question 36

What are the indications for chemotherapy in MCT patients?

Answer 36

High-grade MCT, metastatic MCT, non-resectable MCT, and visceral MCT

Question 37

* Chemotherapy is not indicated for which group of dogs with mast cell tumors? a. High-grade MCTs b. Metastatic MCTs c. Completely excised low-grade MCTs d. Non-resectable MCTs e. Visceral MCTs

Answer 37

c. Completely excised low-grade MCTs

Question 38

What is the MOA of palladia?

Answer 38

To shut of the KIT, VEGFR, and PDGFR receptors

Question 39

True or False: Palladia is FDA-approved for use in cats with MCT

Answer 39

False - dogs with MCT

Question 40

What does the Tigilanol tiglate intratumoral injection do?

Answer 40

PKC activator

Question 41

What are the supportive therapy considerations for MCT?

Answer 41

H1 blocker, H2 blocker, (or) Proton-pump inhibitor (PPI) Antiemetic Appetite stimulant

Question 42

What H1 blockers can you use for MCT patients?

Answer 42

Diphenhydramine and cetirizine

Question 43

What H2 blockers can you use for MCT patients?

Answer 43

Famotidine and ranitidine

Question 44

What PPIs can you use for MCT patients?

Answer 44

Omeprazole

Question 45

What antiemetics can you use for MCT patients?

Answer 45

Maropitant and ondansetron

Question 46

What appetite stimulants can you use for MCT patients?

Answer 46

Capromorelin

Question 47

* Mutation of which gene/receptor is associated with a more guarded prognosis and worse clinical outcome for dogs with mast cell tumors? a. BRAF b. C-KIT c. VEGF d. PDGF

Answer 47

b. C-KIT

Question 48

What is the general recommendation for feline mast cell neoplasias?

Answer 48

surgical excision

Question 49

What is the median age for cutaneous SCC diagnosis?

Answer 49

10-11 years

Question 50

What anatomic locations have a predilection for cutaneous SCC?

Answer 50

Head/nasal planum and ventral abdomen

Question 51

What is the recommended treatment for cutaneous SCC?

Answer 51

Surgical when feasible +/- radiation therapy +/- chemotherapy

Question 52

What is the most common digital tumor?

Answer 52

digital SCC

Question 53

How is digital SCC treated?

Answer 53

Primarily surgical +/- chemotherapy

Question 54

What is the prognosis for digital SCC?

Answer 54

1-year survival (50-83%) | 2-year survival (18-62%)

Question 55

Melanomas involving ________ often behave in a benign manner.

Answer 55

haired skin

Question 56

How is cutaneous/dermal melanoma treated?

Answer 56

Surgical excision is often curative - histopathological evaluation is important

Question 57

What is the second most common digital tumor?

Answer 57

digital malignant melanoma

Question 58

True or False: Metastasis is more common in digital SCC patients than in digital melanoma patients.

Answer 58

False - it is more common in digital melanoma patients

Question 59

What is the recommended treatment for digital malignant melanoma?

Answer 59

Primarily surgical +/- immunotherapy

Question 60

What is the prognosis for digital malignant melanoma?

Answer 60

1 year survival - 42-57% | 2 year survival - 13-36%