Mast Cell tumors

Question 1

General

Answer 1

MOST COMMON cutaneous tumor of dogs

2nd Most common of cats (1st - basal cell tumor)

Question 2

Systemic form of mast cell tumor?

Answer 2

Mastocytosis

Question 3

Signalment - Dogs

Answer 3

8-9yrs
The Bs: boxer, bull terrier, bostons, bulldog :)
Pugs - multiple benign
Shar pei - more aggressive

Question 4

Signalment - Cat

Answer 4

8-9 yrs

Siamese

Question 5

Cutaneous location

Answer 5

Anywhere a mast cell is.
Trunk> extremities > head and neck
Cats - head and neck
Tend to be solitary

Question 6

The great imitator

Answer 6

can look like any tumor

Lipoma - ill defined, soft, edematous

Question 7

Pathophysiology

Answer 7

comprised of cytoplasmic granules w/ bioactive substances

Question 8

Bioactive substance examples

Answer 8

• vasoactive substance (histamine, prostaglandins)
• heparin-proteoglycan matrix
• chemotactic
• proteolytic
• serotonin

Question 9

Dariers sign

Answer 9

disturbed mast cell -> degranulation -> erythema, swelling, anaphylaxis, hypotension :(

Question 10

Effects of degranulations

Answer 10

GI ulcers
Delayed wound healing
Hypotension
Local hemorrhage

Question 11

Controlling degranualtion

Answer 11

H1 antagonists (diphenhydramine)
Warn about delayed healing

Question 12

Work up and staging

Answer 12

MDB and Regional lnn aspirates
Thoracic met evaluation
Abdominal US
Bone marrow aspiration
Classification system

Question 13

MDB and Regional lnn aspirates

Answer 13

only thing required if no neg prognostic factors and amenable to wide excision

Question 14

Thoracic mets evaluation

Answer 14

MCT don’t met to lungs.

observe lnn but not very specific

Question 15

Bone marrow aspiration

Answer 15

low yield unless 
Visceral MCT (rare) - BM involved 50% of the time

Question 16

Classification system

Answer 16

stage 0-4
Substage
A - no systemic signs
B systemic illness

Question 17

Histological classification Cats

Answer 17

Mastocytic (more common)
- compact (common), act benign. sx curative
- diffuse - aggressive
Histiocytic
- can spontaneously regress, young siamese

Question 18

Histological classification dog

Answer 18

Patnik 3 tier system :/
Kiupel 2 tier system :)
-based on FNA

Question 19

Treatment - localized skin tumor

Answer 19

wide excision: 2-3cm w/ fascial plane

adjunct chemo for high grade

Question 20

Treatment - localized, non-resectable

Answer 20

RT alone - 1yr
Chemo to down stage then sx!
chemo alone - short lived

Question 21

Treatment - unsuccessful excision

Answer 21

• Scar reversion!!
• Surveillance (only 20-30% reoccur)
• RT
• Chemo

Question 22

Treatment - disseminated disease w/ local tumor

Answer 22

start w/ chemo, local excision and RT if stable and non progressive

Question 23

Treatment Chemo

Answer 23

high risk dogs (mets or high grade)
red/vinblastine
Cyclophasphamide/VBL

Question 24

Treatment Palladia

Answer 24

30% express c-kit mutation

Question 25

Patient related prognostic factors

Answer 25

breed - better for the Bs
Systemic - worse if signs
Location
Stage - lower w/o mets is better

Question 26

Location prognostic

Answer 26

SQ - better
Subungual, oral, mm associated - worse
Visceral or BM - BAD

Question 27

Tumor related prognostic factors

Answer 27

Size - >5cm worse
Growth rate - slow growth is better
Molecular markers - worse w/ c-kit
proliferation rate
Microvessel density
recurrence
Histological grade - well differentiated is better
Multiple tumors - NBD