Mast Cell Tumors Flashcards
What is the most common cutaneous tumor in cats?
1. Basal cell tumor
2. Mast cell tumor
What is the most common cutaneous tumor in dogs?
MCT
True or False: Mast cell tumors are generally very treatment responsive
TRUE
What dog breeds are predisposed to getting mast cell tumors?
- The B breeds, boxers and brachycephalics
- Boxers
- Bulldogs
- Boston terriers
- Bull terrier
(Luckily they get lower grade/less aggressive variants of MCTs)
What cat breeds are predisposed to getting mast cell tumors?
- Siamese cats
Why are MCT’s known as the “great imitators”?
- Lots of different appearances
- Ill defined, soft and edematous (often misdiagnosed as lipoma)
- Tends to be solitary but can have multiple on presentation
Where are cutaneous MCTs usually located on dogs vs cats?
Dogs: Trunk and extremities
Cats: Head and Neck
What is the Darriers sign?
- Disturbance of mast cell tumors leads to degranulation causing erythema, swelling, anaphylaxis and hypotension
(This is why we pre med with Diphenhydramine before poking with needle for FNA)
What are the effects of Degranulation with MCTs?
- GI ulcers (histamine increases HCL in stomach)
- Delayed wound healing / Surgical dehiscence
- Hypotension
- Local hemorrhage
How would you work up and stage for a MCT?
1. MDB
2. Regional LN aspirate
(Only 2 tests needed to stage if no negative prognostic factors and amendable to wide excision! No thoracic rads needed bc doesn’t met to lungs!)
- ABD Ultrasound to check mets to liver and spleen
- BM aspirate if visceral MCT
What can be found on AUS when working up and staging for a MCT?
- Looking for mets to liver and spleen
List the histological classifications of MCTs in cats
1. Mastocytic (most common)
(2 subtypes: Compact of Diffuse, compact most common in cats)
- Histiocytic (seen in young Siamese) - rare
- Splenic / Visceral MCT
- Intestinal MCT
What is known about histiocytic MCTs in cats?
- Seen in young siamese cats
- Requires wide surgical excision
- Can spontaneously regress over 4-24 months (ok to wait it out and see in this case only)
- Rare overall (most common is the mastocytic type)
A siamese cat is presenting for recheck of a cutaneous lesion on the neck, first noticed 5 months ago. On PE today, there is no evidence of a mass. Which type of MCT in cats has the possibility of spontaneous regression?
A. Compact mastocytic MCT
B. Histiocytic MCT
C. Splenic / Visceral MCT
D. Intestinal MCT
B. Histiocytic MCT
What systems are used to grade MCTs in dogs?
- Patnaik 3 tier system (Grade 1,2,3)
- Kiupiels 2 Tier system (Low grade 2 vs High grade 2)