Round Cell Tumors

Question 1

Mast Cell Tumors

Characteristics

Answer 1

Can look like anything!

Mass can come and go (Darier’s sign)

Mild flushing, lump

FNA and it keeps bleeding

Question 2

Mast Cell Tumor

What is it?

Answer 2

Mast cell granules (histamine, heparin, other bioactive compounds)

Question 3

Mast Cell Tumor

Paraneoplastic Syndromes

Answer 3

GI ulceration 
Impaired healing locally
Coagulopathy 
Urticaria
Eosinophilia
Basophilia

Question 4

Mast Cell Tumors

Signalment

Answer 4

Dogs: Boxer, Boston Terrier, Labrador Retrievers, Schnauzers, Beagles, Pugs

Cats: Siamese

Age: any age, usually older in cats

Question 5

Mast Cell Tumors

Dogs

Answer 5

Most commonly have external skin masses

Primary internal tumors are very rare

Question 6

Mast Cell Tumors

Cats

Answer 6

Equal external and internal tumors

Primary symptoms not always skin

Question 7

Mast Cell Tumors
Diagnosis
Cytology

Answer 7

Round cell tumor!

Usually give you a good idea it is a mast cell tumor so surgery and staging can be planned

Question 8

Mast Cell Tumors
Diagnosis
Histopathology

Answer 8

Required for grading the tumor

Must submit margins

Question 9

Canine Mast Cell Tumors

Grade 1

Answer 9

Well differentiated, superficial

Prognosis nearly always good

Question 10

Canine Mast Cell Tumors

Grade 2

Answer 10

Well to medium differentiation
SQ involvement

Variable prognosis
Can do high and low grade within this grade

Question 11

Canine Mast Cell Tumors

Grade 3

Answer 11

Poorly differentiated

Prognosis nearly always very poor

Question 12

Canine Mast Cell Tumors

Prognosis: Mitotic Index

Answer 12

< 5 mitoses/10 hpf, less likely to recur or metastasize

> 5 mitoses/10 hpf, more likely to recur or metastasize

Question 13

Canine Mast Cell Tumors

Stage 0

Answer 13

One tumor, already excised from dermis

Question 14

Canine Mast Cell Tumors

Stage I

Answer 14

One tumor

Question 15

Canine Mast Cell Tumors

Stage II

Answer 15

One tumor, with regional lymph node involvement

Question 16

Canine Mast Cell Tumors

Stage III

Answer 16

Multiple dermal tumors, large infiltrating tumors, or without lymph node involvement

Question 17

Canine Mast Cell Tumors

Stage IV

Answer 17

Any tumor with distant metastasis or recurrence with metastasis

Question 18

Mast Cell Tumors

Treatment: Symptomatic therapy

Answer 18

Not always needed

H1 blocker: diphenhydramine (prevent bronchoconstriction, vasodilation)

H2 blocker:
cimetidine, ranitidine, famotidine
Prevent gastric ulcerations

Prednisone (shrinks tumor)

Question 19

Canine Mast Cell Tumors
Treatment
Surgery

Answer 19

Surgery; 3 cm margins

Question 20

Canine Mast Cell Tumor
Treatment
Electrochemotherapy

Answer 20

Great small low grade tumors
>50% do not come back
2 treatments, 2 weeks apart

Question 21

Canine Mast Cell Tumor
Treatment
Traditional Chemotherapy

Answer 21

Used only for high stage/systemic disease (all grade 3)

Minimally effective alone

Prednisone, Vinblastine, Lomustine
Vinblastine and Pred

Question 22

Canine Mast Cell Tumor
Treatment
Tyrosine Kinase Inhibitors

Answer 22

Toceranib (Palladia) 
50% chance of response
Response for about 2 months
Toxicity
On it for life

For more aggressive tumor

Question 23

Canine Mast Cell Tumors
Prognosis
Grade 1

Answer 23

Most cured with surgery (83%)

Can irradiate/electrochemotherpay

Surgery not possible

Question 24

Canine Mast Cell Tumors
Prognosis
Grade 2

Answer 24

Surgery can be curative (44%) - low and high grade

Radiation often needed as follow-up (80% cured)

Some require systemic therapy (traditional chemotherapy or tyrosine kinase inhibitor)

Question 25

Canine Mast Cell Tumors Prognosis Grade 3

Answer 25

Surgery rarely curative (6%) Can irradiate if no confirmed metastasis All require systemic therapy (not curative, addition to local therapy)

Question 26

Feline Mast Cell Tumor | Skin

Answer 26

Usually benign Cured with surgery, may have to irradiate depending on location (ex. eye)

Question 27

``` Feline Mast Cell Tumors Internal Form (2 kinds) ```

Answer 27

More aggressive Two forms: Lymphoreticular Gastrointestinal

Question 28

Feline Mast Cell Tumors Internal Form Diagnostics

Answer 28

Mass in abdomen: aspirate yields mast cells Often circulating mast cells in blood (see on smear) -- this would be bad in dogs but normal for cats

Question 29

Feline Internal Mast Cell Tumors | Treatment

Answer 29

Symptomatic: Pred, H1 and H2 blockers Remove tumor; spleen or intestine Tyrosine Kinase inhibitors shown to be beneficial

Question 30

Feline Internal Mast Cell Tumors | Splenic vs Intestinal

Answer 30

Splenic: could stop therapy after surgery Intestinal: may require therapy for life

Question 31

Feline Internal Mast Cell Tumors | Survival

Answer 31

Splenic: > 3 years GI: 11 months (usually spread out more)

Question 32

Histiocytic Sarcomas | What is it

Answer 32

Round cell sarcoma (more concerning) Very high grade sarcoma Cell type of macrophage origin; macrophages or dendritic antigen presenting cells

Question 33

Histiocytic Sarcomas | Signalment

Answer 33

Breeds Flat Coated Retrievers Golden Retrievers Rottweillers Any age, sex, or breed really

Question 34

Histiocytic Sarcomas | Presentation

Answer 34

Masses often associated with muscle groups or joints but can be anywhere Painful Chronic trauma to joint may predispose them (over activation of the immune system)

Question 35

Histiocytic Sarcomas | Diagnosis

Answer 35

IHC needed

Question 36

Histiocytic Sarcomas Treatment Surgery

Answer 36

If removable with minimal morbidity (must make sure that it has not metted) May require amputation

Question 37

Histiocytic Sarcomas | Staging (3 things to look at)

Answer 37

Draining lymph node; although sometimes the tumor appears to arise in a lymph node Lungs; round cells like lungs Abdomen; liver and spleen

Question 38

Histiocytic Sarcomas Treatment Radiation Therapy

Answer 38

Palliative protocol

Question 39

Histiocyctic Sarcomas | Chemotherapy

Answer 39

Lomustine works very well

Question 40

Histiocytic Sarcomas | Prognosis

Answer 40

Rarely curable but will initially respond to treatment Median surival 9 months with radiation and Lomustine

Question 41

Histiocytoma | What is this?

Answer 41

Langerhans cell (round cell) Presents for dermal nodule in a young dog, often on extremities Spontaneously regress or removal (does not require you to remove it though) Cytology = diagnostic

Question 42

Histiocytic sarcoma | Hemophagocytic Form

Answer 42

Malignant Histiocytosis Most likely phagocytic macrophages (eats RBCs) Most common in Bernese Mountain Dog! Presents for severe anemia No effective treatment