Round Cell Tumors Flashcards
Mast Cell Tumors
Characteristics
Can look like anything!
Mass can come and go (Darier’s sign)
Mild flushing, lump
FNA and it keeps bleeding
Mast Cell Tumor
What is it?
Mast cell granules (histamine, heparin, other bioactive compounds)
Mast Cell Tumor
Paraneoplastic Syndromes
GI ulceration Impaired healing locally Coagulopathy Urticaria Eosinophilia Basophilia
Mast Cell Tumors
Signalment
Dogs: Boxer, Boston Terrier, Labrador Retrievers, Schnauzers, Beagles, Pugs
Cats: Siamese
Age: any age, usually older in cats
Mast Cell Tumors
Dogs
Most commonly have external skin masses
Primary internal tumors are very rare
Mast Cell Tumors
Cats
Equal external and internal tumors
Primary symptoms not always skin
Mast Cell Tumors
Diagnosis
Cytology
Round cell tumor!
Usually give you a good idea it is a mast cell tumor so surgery and staging can be planned
Mast Cell Tumors
Diagnosis
Histopathology
Required for grading the tumor
Must submit margins
Canine Mast Cell Tumors
Grade 1
Well differentiated, superficial
Prognosis nearly always good
Canine Mast Cell Tumors
Grade 2
Well to medium differentiation
SQ involvement
Variable prognosis
Can do high and low grade within this grade
Canine Mast Cell Tumors
Grade 3
Poorly differentiated
Prognosis nearly always very poor
Canine Mast Cell Tumors
Prognosis: Mitotic Index
< 5 mitoses/10 hpf, less likely to recur or metastasize
> 5 mitoses/10 hpf, more likely to recur or metastasize
Canine Mast Cell Tumors
Stage 0
One tumor, already excised from dermis
Canine Mast Cell Tumors
Stage I
One tumor
Canine Mast Cell Tumors
Stage II
One tumor, with regional lymph node involvement
Canine Mast Cell Tumors
Stage III
Multiple dermal tumors, large infiltrating tumors, or without lymph node involvement
Canine Mast Cell Tumors
Stage IV
Any tumor with distant metastasis or recurrence with metastasis
Mast Cell Tumors
Treatment: Symptomatic therapy
Not always needed
H1 blocker: diphenhydramine (prevent bronchoconstriction, vasodilation)
H2 blocker:
cimetidine, ranitidine, famotidine
Prevent gastric ulcerations
Prednisone (shrinks tumor)
Canine Mast Cell Tumors
Treatment
Surgery
Surgery; 3 cm margins
Canine Mast Cell Tumor
Treatment
Electrochemotherapy
Great small low grade tumors
>50% do not come back
2 treatments, 2 weeks apart
Canine Mast Cell Tumor
Treatment
Traditional Chemotherapy
Used only for high stage/systemic disease (all grade 3)
Minimally effective alone
Prednisone, Vinblastine, Lomustine
Vinblastine and Pred
Canine Mast Cell Tumor
Treatment
Tyrosine Kinase Inhibitors
Toceranib (Palladia) 50% chance of response Response for about 2 months Toxicity On it for life
For more aggressive tumor
Canine Mast Cell Tumors
Prognosis
Grade 1
Most cured with surgery (83%)
Can irradiate/electrochemotherpay
Surgery not possible
Canine Mast Cell Tumors
Prognosis
Grade 2
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)
Canine Mast Cell Tumors
Prognosis
Grade 3
Surgery rarely curative (6%)
Can irradiate if no confirmed metastasis
All require systemic therapy (not curative, addition to local therapy)
Feline Mast Cell Tumor
Skin
Usually benign
Cured with surgery, may have to irradiate depending on location (ex. eye)
Feline Mast Cell Tumors Internal Form (2 kinds)
More aggressive
Two forms:
Lymphoreticular
Gastrointestinal
Feline Mast Cell Tumors
Internal Form
Diagnostics
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
Feline Internal Mast Cell Tumors
Treatment
Symptomatic: Pred, H1 and H2 blockers
Remove tumor; spleen or intestine
Tyrosine Kinase inhibitors shown to be beneficial
Feline Internal Mast Cell Tumors
Splenic vs Intestinal
Splenic: could stop therapy after surgery
Intestinal: may require therapy for life
Feline Internal Mast Cell Tumors
Survival
Splenic: > 3 years
GI: 11 months (usually spread out more)
Histiocytic Sarcomas
What is it
Round cell sarcoma (more concerning)
Very high grade sarcoma
Cell type of macrophage origin; macrophages or dendritic antigen presenting cells
Histiocytic Sarcomas
Signalment
Breeds
Flat Coated Retrievers
Golden Retrievers
Rottweillers
Any age, sex, or breed really
Histiocytic Sarcomas
Presentation
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)
Histiocytic Sarcomas
Diagnosis
IHC needed
Histiocytic Sarcomas
Treatment
Surgery
If removable with minimal morbidity (must make sure that it has not metted)
May require amputation
Histiocytic Sarcomas
Staging (3 things to look at)
Draining lymph node; although sometimes the tumor appears to arise in a lymph node
Lungs; round cells like lungs
Abdomen; liver and spleen
Histiocytic Sarcomas
Treatment
Radiation Therapy
Palliative protocol
Histiocyctic Sarcomas
Chemotherapy
Lomustine works very well
Histiocytic Sarcomas
Prognosis
Rarely curable but will initially respond to treatment
Median surival 9 months with radiation and Lomustine
Histiocytoma
What is this?
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
Histiocytic sarcoma
Hemophagocytic Form
Malignant Histiocytosis
Most likely phagocytic macrophages (eats RBCs)
Most common in Bernese Mountain Dog!
Presents for severe anemia
No effective treatment
