Cytology

Question 1

The gold standard is to send all samples except one to a pathology lab. Why is this sometimes not done? Why do you keep one slide for yourself?

Answer 1

Financial or time restraints

Assess quality

Question 2

Do you stain slides?

Answer 2

Only if viewing in house

Question 3

Why should you keep cytology slides away from formalin if taking a histopathology sample at the same time?

Answer 3

Fumes destroy cytology

Question 4

What are the advantages of cytology?

Answer 4

Fairly non-invasive
Cheap
Can be done consciously

Question 5

What are the 4 types of cytology?

Answer 5

Fine needle biopsy, with or without aspiration
Impression smear
Tape strip
Swab

Question 6

When would you use a fine needle biopsy with aspiration? Give examples

Answer 6

More structured tissues
Don’t exfoliate well
e.g. muscle, fibromas or soft tissue sarcoma

Question 7

When would you use fine needle biopsy without aspiration? Give examples

Answer 7

Less structured tissues - softer, vasculised tissues
Cells exfoliate easily
E.g. lymph nodes, spleen, liver

Question 8

How do you do a fine needle biopsy without aspiration?

Answer 8

Prepare mass aseptically
Secure mass with non-dominant hand
Insert needle and redirect several ties without removing
Withdraw needle and apply pressure to site to stop bleeding
Draw up 5ml air and connect to needle
Expel onto slide
Wipe across with other slide and leave to airdry

Question 9

How do you do a fine needle biopsy with aspiration?

Answer 9

Prepare mass aseptically
Secure mass with non-dominant hand
Insert needle into mass with syringe attached - draw syringe back 2-3 mls
Maintain this -ve pressure and redirect.
Release pressure before removing needle from mass and syringe
Apply pressure into site
Draw air into syringe and reattach to needle and expel

Question 10

What are the disadvantages of cytology?

Answer 10

May not be diagnostic quality
Very small sample size
Can induce haemorrhage
Can’t use in highly vascular masses or animals with coagulation defect

Question 11

When is an impression spear useful?

Answer 11

Ulcerated masses
Skin pathologies
Sample from excised masses

Question 12

How do you do an impression smear?

Answer 12

Blot surface to remove blood contamination
Do not prepare
Press clean slide onto sample and allow to air dry

Question 13

What is a tape strip useful for?

Answer 13

Identifying surface infectious agents e.g. between digits

Question 14

Describe how a tape strip is done

Answer 14

Do not prepare area
Measure sellotape 2cm longer than slide
Press tape in area of interest
Bring tape around other side of slide and attach halfway down to get a loop
Stain in solutions B and C - not A is fixative melts glue on tape
Unstick end from halfway and flatten it
Blot away excess stain

Question 15

When is a swab useful?

Answer 15

Skin cytology

Ear, nasal, ocular, vaginal, fistulae

Question 16

How do you do a swab?

Answer 16

Use a sterile swab and roll over areas of interest
Roll swab over the microscope
If the sample is greasy e.g. cerumen heat fix the slide with a hairdryer to melt wax and expose cells to stain
Stain

Question 17

What should you do when viewing the quality of slide?

Answer 17

Start at low power and work up
Check distribution and stain of cells
Describe cells and organisms visible
Check the sample is of the intended tissue

Question 18

What size needle should be used in FNA?

Answer 18

22G

Question 19

Why would you not use a different size needle?

Answer 19

Small needle decreases cell yield

Larger needle would induce haemorrhage and dilute sample

Question 20

How many slides should be prepare for FNA?

Answer 20

4

1 to check in house

Question 21

What should be done in preparation for any lab skills?

Answer 21

Hair up
Put lab coat on
Put gloves on