16 terms

Canine Mast Cell Tumors - Study Questions

Can they be diagnosed with cytology or is histopath necessary?
Cytology is the best way to diagnose and determine spread
Histopath is needed for grading
How does length of time the tumor has been present affect prognosis?
If the tumor has been there longer than 6 months and hasn't recently grown, it has a better prognosis
Canine mast cell tumors are most common in what tissue?
In what tissue and organs can they occur?
Cutanous (metastasis to local LN, spleen, liver, bone marrow)
Visceral (spleen, liver, GI, renal)
Is there anything on a CBC and chemistry profile that is diagnostic for mast cell tumors?
The peripheral blood may have mast cells with severe disease, but otherwise no
What are known causes?
Breed - Rhodesian ridgebacks, boxers, labs, goldens
Areas of chronic inflammation
Genetic mutation - tyrosine kinase encoding gene c-kit
Why is it important to give dogs that have mast cell tumors present antihistamines?
Prevent edema around tumor, allergic-type reaction, and gastric ulcers
Which histamine receptors do we try to block?
H2 (more important)
If cutaneous mast cell tumors metastasize, to which location do they spread first?
Local lymph node
What are prognostic indicators that suggest a mast cell tumor might metastasize?
Grade (I-III) - higher more likely
Mitotic index - > or = have high risk of recurrence and metastasis
For cutaneous mast cell tumors what is the best treatment?
Surgical removal - 2 cm laterally and 1 fascial plane deep
Are multiple cutaneous mast cell tumors a poor prognosis?
No - remove them all and treat based upon worst grade
What mitotic index is a poor prognosis?
> or = 5
What is the prognosis of each of the 3 grades?
Grade III is worst - poor prognosis
What chemotherapy agents are effective for treating mast cell tumors?
Toceranib, mastinib
What is the general histopath description of each grade?
Grade I - well-differentiated mast cells, mitotic cells absent
Grade II - moderately pleomorphic cells arranged in groups, mitotic cells are rare
Grade III - neoplastic cells are pleomorphic, cytoplasm is indistinct with fine, intracytoplasmic granules, mitotic cells are common