Ch. 20 Biopsy Principles

Question 1

What depth should a cutting needle biopsy device be inserted to?

Answer 1

1.5 cm or greater into the tissue to be sampled so that the entire sample notch is within the tissue

Question 2

Name three aspiration core needle biopsy varieties

Answer 2

Jamshidi - has an internal bevel that allows for a large sample aquisition
Klatskin - also has an internal bevel
Menghini - suction based approach

Question 3

Name two cutting core needle biopsy

Answer 3

Tru cut

Franklin-Silverman

Question 4

What size needle should be used for renal core biopsies?

Answer 4

14 gauge

Question 5

According to Tobias but not real life, where should biopsy samples be obtained?

Answer 5

At the periphery of the lesion - the junction of the normal and abnormal tissue

Question 6

What is the theory behind sentinel lymph node sampling?

Answer 6

If metastasis is located within this lymph node, it is more likely to be in other lymph nodes in that lymphocentrum, but if the sentinel lymph node is negative for metastasis, other lymph nodes in that lymphocentrum are also likely negative

Question 7

What is the most common complication of liver biopsy?

Answer 7

hemorrhage

Question 8

How many endoscopic samples are recommended for the stomach, small intestines, and large intestines?

Answer 8

6-8 gastric
10-15 small intestines
3-4 large intestines

Question 9

How often will surgical biopsies yield a final diagnosis for sampling of the GI tract?

Answer 9

94% of cases

Question 10

When might renal biopsies be indicated?

Answer 10

glomerular disease (like PLN)
acute renal failure unresponsive to medical therapy
**the goal is to obtain CORTICAL tissue

Question 11

Name some contraindications to renal biopsy

Answer 11

bleeding disorder, severe anemia, uncontrolled hypertension, pyonephrosis or abscess, hydronephrosis

Question 12

Why do we only want to sample the renal cortex?

Answer 12

Cortical tissue should be sufficient for a diagnosis
sampling the medulla carries a significantly increased risk of hemorrhage (renal vessels increase in size) as well as an increased risk of infarction and fibrosis
wedge biopsies can be performed with an open surgical approach but may require temporary vascular occlusion to the kidney

Question 13

What is the most common complication of renal biopsy?

Answer 13

hemorrhage
occurs in 10% of dogs and 15% of cats with normal clotting profiles
Other risks include AV fistula formation, cyst formation, infarction, thrombosis, infection, fibrosis, rarely hydronephrosis

Question 14

How should you obtain a pancreatic biopsy?

Answer 14

right distal limb is recommended location because it is farthest from the pancreatic ducts and duodenal vasculature
use laparoscopic punch biopsy over laparoscopic cup because punch biopsy cuts while cup tears
when using the laparoscopic punch, grasp and hold the tissue for 30 seconds prior to avulsion to aid in hemostasis

Question 15

Can you use a bipolar vessel sealing device to obtain a lung biopsy?

Answer 15

yes - but for biopsies that are 3 cm or more from the edge of the lung lobe, suture techniques and staplers/ligation devices are recommended because the bipolar vessel sealing device had inconsistent sealing and consistent leakage at lung pressures below normal thresholds