Mast Cell Tumor

Front 1

Round cell tumor (lymphoma, MCT)

Back 1

in general substantial remission w/ chemo but not cure. Most cases relaspes and die except MCT

Front 2

microscopic dz vs. macroscopic dz

Back 2

micro dz response beter to chemo, macroscopic dz rarely response to chemo except lymphoma (round cell)

Front 3

MCT

Back 3

ALL ARE DIFFERENT
majority in skin can cure, some die, hard to tell owner if dog will cure
3rd most common GI tumor (1st lymphoma, 2nd adenocarcimona)

Front 4

Cutaneous MCT in cats

Back 4

2nd most common cutaneous tumor
cats usually do great
affects older cats
Histiocytic form affects younger cats: Siamese predisposed, 2yr, get lumps all over face, GO AWAY when they are older

Front 5

Prognosis of MCT in cats

Back 5

cutaneous- good
Gut- bad
spleen- do good with splenectomy

Front 6

MCT in dogs

Back 6

most common cutaneous/ sub Q neoplasm in dogs
older dogs, both sexes, any breed but boston, boxer, pugs and lab predisposed
start i skin, go to viscera, most cure with surgery alone, but some bad

Front 7

History of MCT

Back 7

varies, depend on form of MCT, most just sub Q mass, GI sign may occur due to histamine secreted by tumor
Dogs: well differentialed tumor solitary, slow growing and firm, poorly differentiated tumor: aggresive, rapid growth, potentially intermittent swelling and pain
Cats: splenic and GI tumor non specific sign, inappetance, lethargy, vomiting, diarrhea

Front 8

PE of MCT

Back 8

cutaneous lesion: single firm nodules, multiple possible
cutaneous or sub Q
Cutaneous ones can be haired, ulcerated, reddened, painful
consistancy of sub Q lesion SIMILAR TO LIPOMA

Front 9

3 distant form of MCT in cats

Back 9

1. Cutaneous (very rare Sub Q) on head and neck
2. Splenic (just ill) with splenomegaly, diffusely enlarged but sometimes nodular
3. GI form (vomiting, diarrhea)- intraabdominal mass palpated, may be solitary or multiple

Front 10

Dog MCT (a continuum from skin to visceral form)

Back 10

Cutaneous or SubQ lesion
MCT CAN FEEL JUST LIKE A LIPOMA
Visceral MCT is rare and almost always spread from cutaneous lesion

Front 11

Differential ddx for MCT

Back 11

eosinophilic granuloma complex (need cytology)
severe flea allergy dermatitis or other allergic dermatopathy
neoplasia
basal cell tumor
splenomegaly with rickettsial dz

Front 12

Nasal tumor

Back 12

Locally invasive, not really mets, RT tx of choice, cats with nasal lymphoma can also do chemo

Front 13

Anal gland tumor

Back 13

locally non- invasive but difficult to get to, likely to mets

Front 14

Osteosarcoma

Back 14

locally invasive and mets

Front 15

Diagnostic for MCT

Back 15

1. CBC and bone marrow buffy coat- see next card
2. chem and UA- wnl, may have high liver enzyme if liver infiltrated
3. ab radiograph/ US- dogs only, spleen, liver and nodes involvement with visceral invasion
4. thoracic rads- RARELY METS TO LUNGS, only to evaluate sternal LN if lesion in ventral ab or visceral dz exists
5. cytology- uniform population of round cells with purple staining granules. Sometimes need Giemsa stain cause they may not stain well
6. biopsy- Impt for grading, but not needed for ddx, do not routinely premed with diphenhydramine or H2 blocker (worry about histamine and heparin secreted by MC)

Front 16

CBC and bone marrow buffy coat

Back 16

buffy coat for cats but NOT DOGS cause non- MCT dogs can have mastocytosis while MCT dogs don't.
Cats with splenic MCT have peripheral mastocytosis so can do buffy coat.
Marrow invasion can occur w/o mastocytosis in both species so do BM aspirate instead.

Front 17

DO NOT STAGE CATS WITH CUTANEOUS MCT UNLESS ODD CLINICAL APPEARANCE, SUCH AS SYSTEMIC SIGNS

Back 17

cats with cutaneous MCT RARELY have visceral involvement

Front 18

cutaneous allergic rxn vs. MCT in cytology

Back 18

based on relative numbers of inflam cells present.
MCT= lots of MC, rare ros
inflam rxn= lots of eos and netrophils, rare MC

Front 19

GRADING for Cat's MCT

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NO GRADING FOR CATS MCTs
form of dz determines bio behavior

Front 20

Grading for dog MCT (take with grain of salt, only one criteria, also depend on location and LN aspiration)

Back 20

don't need biopsy for ddx but needed for grading, need wide margin, all grow fingers
Grades help to predict bio behavior
grade 1- normal looking mast, distinct granules, no mitosis ( curable)
grade 2- moderately differentiated, fine granules, rare mitosis (curable most of the time)
grade 3- poorly differentiated, pleomorphic cells, poorly granulated (usually mets)
hard to see with dip quick sometimes, need to send in for gimesa stain

Front 21

Mitotic rate

Back 21

good predictor for outcome for dog MCT regardless of grade
need to be done by pathologist

Front 22

Prognostic factors for dogs

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1. breed- boxers more likely but also less aggressive form
2. Growth rate- good if slow growth and stable, bad if rapid growth
3. Clinical appearance- bad if ulcerated, fixed or invasive
4. Location and extent of dz: muzzle, pinna, nail bad, oral- bad. Preputial and scrotal= worse, viseral and bone marrow involvement- bad
5. clinical signs- GI signs worst, localized d better than disseminated dz
6. Systemic sings- clincally normal animal better than ill
7. histological grade= very subjective, depend on pathologist. Grade 1 and 2 better than 3
Mitotic rate: lower rate better

Front 23

Bio behavior of MCT

Back 23

canine and feline MCT contain histamine and heparin, feline MCT also containt serotonin
signs related to histamine: hyperremia, pruritis, swelling and pain, GI signs (histamine induced HCl secretion from peripheral cell)
Heparin= increased bleeding time, wound healing compremised

Front 24

Cats MCT( 3 form, 3 behavior)

Back 24

1. Cutaneous:
a. histocytic type: spontaneously resolve w/o surgery
b. Mast cell type= not assoc. with visceral dz
2. Splenic: circulating mastocytosis and liver involvement, survival prolonged (12- 18m) with splenectomy
3. GI: even though one mass grossly, infiltrate microscopically throughout tract, poorly responsive to surgery or chemo

Front 25

Dogs MCT: cutaneous (one form but multiple behavior possible)

Back 25

locally invasive even if well differentiated
mets may occur to local ln, spleen, liver or BM
NO METS TO LUNGS
higher grade more likely to recur
ALWAYS SEND IN, can look like anything, have to poke a couple of times cause they exfoliate

Front 26

Treatment for MCT: surgical excision

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wide margin required for dogs not cats (not locally invasive)
curative for single well to moderately differentiated mass

Front 27

Treatment for MCT: RT

Back 27

well to moderately diff. mass that is incompletely excised can be cured with post op RT
RT for gross dz may control growth but not curative

Front 28

Treatment for MCT: chemo

Back 28

canine MCT response better
not curative in most cases
extend survival of grade 3 or systemic dz, non- resectable dz, may be curative to microscopic residual local dz
pred and vinblastine used

Front 29

TK inhibitor

Back 29

block singal transducion leading to cell death
Palladia 1st FDA approved vet anti- cancer drug
60% response rate

Front 30

Ancillary therapy (KNOW)

Back 30

HI(benedryl) and H2(famotidine) blocker for life or till dz remission
Antihistamine and anitserotonergic agents, mucosal protectants as needed
all dogs with bulky MC dz (visible or disseminated dz)