MCT, Skin and Bone Tumors Flashcards
Where do Mast cell tumors originate?
Bone marrow
Where do MCT mature?
Tissues
What do the Mast cell granules contain?
Histamine, heparin, tissue degrading proteases
What are the classic signs of inflammation?
Swelling, heat, redness, pain
What enzyme is mutated that leads to Mast Cell Tumor formation?
C-kit (tyrosine kinase)
T/F: MCT is the most common skin tumors in dogs
True
What are some breeds that are predisposed to MCT?
Boxer, Vizsla, Boston Terrier, Shar-Pei, Dutch Pug
Where are some common areas on the body to find MCT?
Trunk/perineal region, limbs, head/neck
What signs are associated with histamine?
GI - vomiting, anorexia
Hives, pruritis
Wheezing
Hypotension
What would you see in cytology for MCT?
Round, discrete cell tumors
Large round cells with purple granules
What are some ways to stage a MCT?
Aspiration of lymph nodes*
U/D of abdomen, bone marrow aspirate
T/F: Thoracic rads and buffy coats are diagnostic staging tools for cutaneous MCT
False. MCT does not spread to the lungs and the buffy boat has false positives
T/F: Even palpably normal lymph nodes can have metastasis
True
What are the metastatic potentials in relation to the grades of the MCT?
Low grade - <10%
Middle grade - <15%
High grade - 90%
What are the factors observed when histologically grading MCT?
Location, architecture, morphography, edema/necrosis
What should you premedicate a patient with MCT with before surgical excision of the tumor?
diphenhydramine
T/F: Wide surgical excisions are required for MCT surgery
True
How large are the excisions for MCT surgery?
2-3 cm margins, 1 fascial plane deep
T/F: Inking of the tumor is always recommended
True
When would you perform radiation therapy on a patient with MCT?
Post-op, if the margins were not possible to completely remove
Is it possible to just give RT alone as treatment?
Yes, but it’s not as good as surgery
When would you perform chemotherapy on patients with MCT?
As a palliative treatment for non-resectable tumors and as an adjuvant for aggressive MCT
What are some chemo drugs that work against MCT?
Prednisone, CCNU, vinblastine, chlorambucil, toceranib, masitinib
What chemo drug directly works against tyrosine kinase, and thus c-kit?
Palladia (toceranib)
What chemo drug would be used after local control of MCT?
Vinblastine, CCNU, Chlorambucil, Prednisone
How can you treat histamine-induced gastic ulceration from MCT?
Diphenhydramine, famotidine, ranitidine, omeprazole, sucralfate
T/F: Advanced/metastatic MCT means a much lower prognosis
True
How should you treat a completely excised grade 1/2 MCT? Incomplete?
Complete - Monitor
Incomplete - re-excise or RT
How should you treat a completely excised grade 3 MCT? incomplete?
Complete - chemotherapy
Incomplete - radiation/chemotherapy
T/F: Feline MCT is associated with FeLV and FIV
False
Which form of feline MCT is most commonly seen?
Mastocytic form
Which form of feline MCT is seen in siamese cats?
Histiocytic form
T/F: Compact Mastocytic MCTs are usually more malignant
False. Diffuse is more metastatic
T/F: Histiocytic MCTs are benign
True
Where do you normally find mastocytic, compact MCT?
Head and neck
T/F: Multiple compact MCT on a feline is a sign of poorer prognosis
False. Not correlated with degree of malignancy or metastasis
How should you treat diffuse miliary cutaneous MCTs?
Chemotherapy, symptomatic (histamine)
T/F: Cats have splenic MCTs more commonly than dogs
True
How do you determine the prognosis of splenic MCTs?
Lymph node metastasis
How would you splenic MCTs?
Surgery and chemotherapy
T/F: Intestinal MCTs metastasize frequently.
True
How should you treat intestinal MCTs?
Remove the tumor with surgery
Where do soft tissue sarcomas arise from?
Embryonic mesoderm - connective tissue
What might be some possible causes of STS?
Breed predisposition, vaccine/microchip injection sites
How do you diagnose STS?
FNA/cytology
What are the most common sites of metastasis for STS?
lungs, liver, lymph nodes
How would you test for staging of STS?
Diagnostic imaging
How should you treat a vaccine associated sarcoma?
2 cm marginal resection
What is the most common primary bone tumor in dogs?
Osteosarcoma
What type of animal usually gets osteosarcoma?
Older and larger
What is the rule with tumor location on the limbs?
Towards the knee away from the elbow
What are some fractures that may lead to osteosarcoma?
metallic implants, chronic osteomyelitis, exposure to ionizing radiation
T/F: Osteosarcomas commonly cross the joints and invade the neighboring bone
False
T/F: Metastasis is very common with osteosarcoma
True
How does osteosarcoma metastasize?
Through the blood/bone marrow
Where does OSA usually metastasize to?
Lungs
What are some major signs of OSA?
Lame, PAIN, swelling
How can you diagnose OSA?
FNA/cytology for most cases
Is ALP staining for OSA useful?
Yes
What is the best choice of treatment for localized OSA?
Surgery
When is it possible to spare the limb with surgery?
If the primary tumor is <50% of the bone and <360` around the tissues
T/F: Dogs typically die from the pain with OSA
False. Systemic disease associated with OSA
What are some chemotherapy options to treat OSA?
Carboplatin, doxorubicin, combination chemo, low dose continuous chemo
