Date post: | 06-Aug-2015 |
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MAST CELL TUMOURS OF THE DOG
Max Doig
9y1m, MN, Labrador Mass first noticed 25th June 2014 Referred last week after diagnosis of MCT
on the left proximal hindlimb (FNA and cytology)
Admitted to the SAH for staging/surgical assessment of mass.
Max also had other lumps that had been diagnosed as lipomas and one suspicious lump in the submandibular region.
Other than multiple masses Max was normal on physical exam.
Whilst admitted:
Haematology and Biochemistry Tumour mapped Chest xrays Abdominal ultrasound + Aspiration of
spleen
Repeat FNA for submandibular lump
General Presentation/clinical signs
Very common Account for 20% of all skin tumours in
dogs Commonly affects middle aged to older
dogs May demonstrate rapid growth Solitary or multiple sites Varied appearance May arise from any skin site on the body Size may alter relatively quickly Gastrointestinal effects (including possible
PNS)
Examples of MCTs
Changes in size
Granules contain: - histamine - heparin - vasoactive amines
Degranulation may occur leading to their release
Local effects
Systemic effects (hyperhistaminaemia – PNS)
Diagnosis
FNA Biopsy- excisional vs incisional
Staging• Regional LN aspiration (if appropriate)• Chest xrays• Abdominal ultrasound• Other tests prior to treatment:
- Haematology/biochemistry- Urinalysis
A modified World Health Organization TNM classification of canine mast cell tumors
Stage Description: 0: One tumour incompletely excised from the
dermis, without regional lymph node involvement
I: One tumour confined to the dermis, without regional lymph node involvement
II: One tumour confined to the dermis, with regional lymph node involvement
III: Multiple dermal tumours or large infiltrating tumour, with or without regional lymph node involvement
IV: Any tumour with distant metastasis or recurrence with metastasis
Grading systems Patnaik (graded 1-3 below) vs Kiupel (low
or high grade)
Treatment
Aim: complete resection• Low grade (1,2)- wide local excision (or radiotherapy in some cases) - Cytoreductive surgery + radiotherapy- Cytoreductive surgery + chemotherapy
• High grade (3)- Wide local excision + chemotherapy (+/- radiotherapy)
Back to Max
Max’s owners decided on surgical excision He is booked in Tuesday 29nd Julyo Marginal resection has been selected by the
owners
Max’s owners decided early on that they did not wish max to receive chemotherapy.
Max was not sent home with any gastrointestinal protectants as he had not exhibited any GI signs. (Anti-histamines were suggested- H1 antagonist)
Chemotherapy
Only indicated for management of high grade malignant/metastatic tumours
Varied response Options include• Vinblastine + prednisolone • Lomustine + prednisolone• Vinblastine + lomustine • Tyrosine kinase inhibitors (Masitinib,
Toceranib)
Radiotherapy
A common protocol would be radiation mon/wed/fri for 4 weeks
May also see daily treatment mon-fri for 3.5-4 weeks
GI Protectants H2 antagonists: • eg Famotidine (0.5-1 mg/kg p.o. q12-24h.)
Omeprazole: • 0.5-1 mg/kg p.o, iv q24h (for maximum of 8weeks)
Sucralfate (if evidence of GI ulceration/bleeding)• If <20kg: 500mg/dog p.o. q6-8h• >20kg: 1-2g/dog p.o. q6-8h
H1 antagonists • eg Loratadine (5-15mg q24h)
Prognosis
Major prognostic factors:• Tumour grade• Mitotic index• Surgical margins• Tumour stage (eg LN involvement)
Minor prognostic factors:• C-kit expression pattern• Ki-67 expression
References J Vet Intern Med. 1990 Sep-Oct;4(5):242-6.Plasma histamine and gastrin concentrations in 17 dogs with mast cell tumors.Fox LE1, Rosenthal RC, Twedt DC, Dubielzig RR, MacEwen EG, Grauer GFhttp://www.ncbi.nlm.nih.gov/pubmed/2124627
Canine Mast Cell Tumorshttp://www.vetmed.wsu.edu/deptsOncology/owners/mastcell.aspx
Mast Cell Tumors http://www.veterinarycancer.com/mastcelltumors2.html
Canine and feline skin tumors (Part 2)James Warland MA VetMB MRCVS, Jane Dobson MA BVetMed DVetMed Dipl. ECVIM-CA and Onc MRCVS - 18/02/2012http://vetgrad.com/show10MinuteTopUp.php?type=&Entity=10MinuteTopUps&ID=78
References continued
Not all lumps are lipomas: Canine Mast Cell Tumours Dr Angela Frimberger VMD, MANZCVS, Diplomate ACVIM(Onc) Dr Antony Moore BVSc, MVSc, MANZCVS, Diplomate ACVIM(Onc)
http://www.ava.com.au/sites/default/files/AVA_website/pdfs/NSW_Division/SMALL%20ANIMAL%20%20Frimberger%20%26%20Moore%20%20Mast%20Cell%20Tumors%20%20Not%20all%20lumps%20are%20lipomas.pdf
Radiation therapy for canine mast cell tumors, Monique N.Mayerhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823470/pdf/16604985.pdf
Mast Cell Tumours (MCTs) http://www.caninecancer.com/Mast.html
Questions?