Surgical Oncology Flashcards
When would you do a pre-treatment biopsy?
FNA is insufficient for surgical planning (false neg, life and death choices/ tumor grade changes approach)
If treatment will be altered by result
If owners willingness to treat is altered by result
If surgery is in a difficult anatomic location
Treatment has high morbidity
you will almost NEVER be wrong to do this
What are the pros to an incisional biopsy?
Better planning for surgery
Ability to establish informed consent
Appropriate implementation of neoadjuvant and adjuvant treatments
When doing a incisional biopsy, where/ should you biopsy site be?/
Avoid ulcerated/inflamed tissue
Plan -closure to not comprise future six
Orient incisions with tension lines
Large and multiple samples are best
What are the techniques to incisional biopsies?
Tru cut
Punch biopsy
Wedge
Jamshedi/Michelle trephine (bone biopsy)
Endoscopic/laparoscopic
T/F: punch biopsies can be used for hypodermal masses?
False
Unless you have visual exposure of the tissue you are sampling
Tissue can shift and undetected hemorrhage can occur
What is the preferred biopsy techqnie for ulcerated or necrotic tumors or a deeply located mass?
Wedge biopsy
Where is the ideal location of procure a wedge biopsy?
At the junction of normal/abnormal tissue
But remember for surgery.. entire biopsy tract must be removed — do not compromise surgery for the biopsy
When would you do an excisional biopsy?
When treatment is not altered by tumor type or grade
If biopsy procedure is invasive or carries high risk (eg spleen)
If location is permisssive of wide margins without compromising tissue for future re-excision if needed
How can you prevent tumor seeding when doing an excisional biopsy?
Minimized hemorrhage
Eliminate all dead space
Do not drain!
Majority of solid tumors are rounded by a ____________ which may contain microscopic tumor extensions or satellite populations of tumors cells
Pseudocapsule (reactive zone)
What is the Enneking system of surgical dose?
Intralesional (curettage or debulking)
Marginal (through pseudocapsule or perilesional zone)
Wide (in normal tissue outside of pseudocapsule )
Radical
What is one of the only applications of an intracapsular excision?
Debulking of lipoma
A carcinoma removed with lateral margins <1cm or a mast cell tumor with <2cm
How is this classified by the Enneking classification?
Marginal
A soft tissue/ bone sarcoma removed with margins >3cm or a feline injection sarcoma removed with >5cm margins is classified how by the Enneking system?
Wide excision
You have an osteosarcoma on the distal radius, you do a limb amputation. How is this classifed by the Enneking system?
Radical
For a mast cell tumor, what are the requirements for a wide excision?
Minimum of 2cm (general rule is 3cm) lateral margins AND a facial deep plane
T/F: the margins of a MCT differ based not he grade fo the tumor
True
Grade 1 tumor has clean excision at 1, 2, or 3 cm
Grade 2 is clean at 3cm, only 90% are clean at 2cm, and only 68% are clean at 1cm
What is the modified proportional margins technique?
Widest diameter of the tumor is used as the LATERAL margin
Eg if tumor s 1.5cm diameter, the lateral margin will be 1.5cm
If greater than 4cm diameter —> fixed lateral margins of 4cm are used
Still use 1 deep fascial plane
What are the surgical margins for a benign tumor?
1cm
What is the surgical margin for a soft tissue sarcoma?
3cm lateral
AND
1 facial plane/ 2 muscle planes deep
Surgical margin for a acanthomatous ameloblastoma?
1cm
Margin or malignancies in the oral cavity?
2cm lateral
Bone margin
T/F: you should always ink surgical margins of tumors
True!!
Do not ink the skin thought
What should you provide on your submission form for your biopsy specimen?
Signalment
Clinical info about the tumor
Anatomical site
Lesion description
List your DDX
What is the formalin: tissue ratio? What is the appropriate thickness formalin can penetrate?
10:1
1cm
For large tissue samples, how you you prepare so they are adequately preserved in the formalin?
Bread loaf — parallel cuts at min 2cm apart
Avoid complete transection or too many cuts — can result in loss of tissue orientation
How can you submit small volume biopsy?
Screen cassette
Placed in jar of formalin
Label cassette if multiple samples
