What is a pre-treatment biopsy? When is it performed? What are the 5 indications? What are the types?
Before definitive treatment to get more info about tumor
1. When FNA has provided insufficient info for surgical planning
2. If type of treatment is dependent on tumor type
3. If it alters the owners willingness to treat
4. Tumor in difficult anatomic location
5. Treatment has a high morbidity
Needle core, Wedge and Punch
What is a post-treatment biopsy? When is it performed?
After surgical removal of tumor to get more complete picutre, evaluate margins
Rarely the first option for getting tissue diagnosis
What type of biopsy would be indicated for a cat that has a firm hypodermal mass? Why?
Because it could be an injection site FSA and would require really aggressive surgery
An incisional biopsy increases the risk of local recurrence. How do you diminish/eliminate this risk?
Remove entire biopsy tract during second surgery
Why is the orientation of incision an important consideration when performing an incisional biopsy?
Must orient along tension lines (longitudinally) and in a direction that won't increase the surgical field for the second surgery
What size punch biopsy is needed to procure a diagnostic sample? For what types of masses is this biopsy counter-indicated?
Do not use for hypodermal masses
What type of biopsy is indicated for ulcerated or necrotic tissues that are deeply located? What instrument do you use to maintain tissue retraction for deeper lying tumors?
What type of biopsy is indicated for a testicular mass?
What type of biopsy is indicated for a lateral thoracic undiagnosed 1cmx1cm dermal mass on a large breed dog?
Why is placing a drain counter-indicated post-excisional biopsy?
Increases risk of tumor seeding
What is the Enneking System? What are the main designations?
Classification of surgical dosing
Intralesional (least invasive) vs Marginal vs Wide vs Radical (most invasive)
Intralesional/capsular= part of tumor and part of capsule
Marginal= part of capsule
Wide and radical= grossly normal tissue cut only
When would you make an intracapsular dissection?
When is a marginal excision indicated? What margins are indicated for different tumor types?
Lateral margins <1cm for carcinoma
<2cm for MCT
<3cm for soft tissue or bone sarcoma
<5cm for feline injectionsite sarcoma
What type of exicsion is indicated for perianal region tumors?
What are, generally, the margins you need to take for a MCT? What if you know it is a Grade I? Grade II? Grade III?
3cm lateral and 1 facial plane deep OR use the widest diameter of tumor as the lateral margin
Grade 1: 1cm
Grade II: 2cm=90% clean, 3cm=100% clean (most common MCT grade)
Grade III: 3cm
Generally, what margins should you take for benign tumors?
1cm lateral and 1cm deep
Generally, what margins should you take for a sarcoma?
1 facial plane or 2 muscle planes deep
Generally, what margins should you take for a oral tumors?
Acanthomatous ameleoblastoma = 1cm + BONE
Malignancies = 1cm laterally + bone deep
What margins of a biopsy should you ink? What colors are best?
All cut surfaces (NOT the skin)
Yellow or Black
What is indicated prior to fixation for a large specimen?
What is a "narrow excision"?
Clean but close
2-5mm of normal tissue between tumor and cut edge
What is the R classification for margin assessment?
R0 = no residual tumor
R1= microscopic residual tumor
R2= macroscopic residual tumor