4. Cytology

Question 1

What is cytology?

Answer 1

the study of cells, their origin, structure, function and pathology
using cells to ID abnormalities or malignancies
we observe cells in sm groups in random distribution with no connection of how they interact with other cells

Question 2

Why do we use cytology?

Answer 2

a diagnostic procedure used in all species
collect cells from a body fluid, mucosal surface, secretion or tissue
examine the cells microscopically
primarily done to differentiate inflammation from neoplasia
also used to investigate skin dz (dermatopathy)

Question 3

What type of things can we identify with cytology?

Answer 3

if properly collected, stored, and processed sampled can give a rapid dx and accurate tx plan
ID benign or malignant masses
ID lesions (bacterial, fungal, parasitic)
the type of fluid in a body cavity

Question 4

What are the advantages of cytology?

Answer 4

no extra or specialized equipment is required
very quick procedure
relatively non-invasive (animal usually awake)
relatively low cost
quick results - same day or within a week

Question 5

What are some disadvantages of cytology?

Answer 5

some training is required to ID the cells present - done by vet or tech
may not be able to ID cells > off to pathologist > added cost/time
May need to supplement with histopathology

Question 6

What is histopathology?

Answer 6

Study of cellular architecture (cells in relation to their neighboring cells) and function
Requires tissue biopsies or lumps
anesthesia often required, a PIECE is surgically removed and fixed in solution

Question 7

What are the advantages of histopathology?

Answer 7

slide examined by a trained pathologist
can give more precise diagnosis

Question 8

What are the disadvantages of histopatholog?

Answer 8

procedure is more involved and requires specialized equipment
more costly, may take several weeks
if a poor sample taken or poor collection method can lead to misdiagnosis

Question 9

What are the different ways to collect cytology samples?

Answer 9

1. swabs
2. scrapings
3. Imprints/impression smears
4. Fine-needle biopsy
5. Tissue biopsy
6. Centesis
7. Transtracheal/bronchial wash

Question 10

How do we collect a cytology sample with a swab?

Answer 10

performed when imprints, scrapings, or aspirates cannot be done
involves using a moistened (with sterile saline) sterile swab for dry lesions or sterile swab for moist lesions
key to remember NOT to rub the swab across the lesion or slide, but to gently ROLL across to collect/transfer cells
Ear swabs require gentle heat fixing, no others should

Question 11

How do we collectin a cytology sample by scraping?

Answer 11

generally used for firm lesions otherwise we can end up with too many cells on our smear
disadvantage is that scraping often superficial, only indicates 2nd bact infection
typically used for dx of demodex

Question 12

What is the procedure for taking a skin scrape?

Answer 12

1. isolate lesion (mass) w/ off hand
2. Blot surface of lesion/mass
3. Hold scalpel blade in dominant hand at 90 angle or perpendicular to lesion
4. Pull blade across lesion several times to remove layer of cells
5. Take collected material and spread on clean microscope slide
6. Can use oil to adhere sample to slide (can no longer stain, especially when looking for parasites)

Question 13

What is an imprint/impression smears?

Answer 13

performed on ext lesions or from tissues removed during surgery or necropsy
Contains fewer cells than scrapings and have a higher amount of contamination than aspirates - superficial lesions often only reflect a secondary infection or inflammation-induced tissue dysplasia

Question 14

What do we do if we surgically remove a sample for histopathology by imprint/impression smears?

Answer 14

slide is gently touched to lesion several times on several slides
for tissues removed surgically the sample is blotted with gauze to remove excess fluid or blood
Sample then gently touched to a clean slide in several spots

Question 15

What do we need to keep in mind when making the imprint/impression smear?

Answer 15

avoid excessive pressure
If it is not viewed immediately, take a fresh cut of the sample and view that

Question 16

What is a fine needle biopsy? Advantages vs disadvantages? What are the two methods

Answer 16

Used for masses, lymph nodes, nodular lesions, and internal organs
advan: avoids superficial contamination
Disadvantage: fewer cells are collected compared to other collection methods
Can be done via aspirate or non-aspirate methods

Question 17

What must you do an duse when doing a microbiological test or a taking a body cavity sample with a fine needle biopsy?

Answer 17

a surgical scrub must be done
For other samples, swabbing area with alcohol
use a 21-25g needle

Question 18

What syringe do we use with FNA?

Answer 18

use 21-25g needle and a 3-20ml syringe
the softer the tissue, the smaller gauge needle/syringe should be used

Question 19

How do we complete an FNA?

Answer 19

1. Prep skin over mass w/ surgical scrub or alcohol
2. Secure the mass with your “off” hand and hold the syringe/needle in dominant hand
3. insert needle into mass + pull back on plunger to create neg pressure
4. Redirect needle several times within mass while maintaining neg pressure
5. Release neg pressure, remove needle from mass
6. Remove syringe from needle, fill syringe with 2-3mls of air
7. reattach needle
8. gentle force sample onto slide
9. Use compression preparation, combination technique or starfish smear to prepare sample

Question 20

With a FNA, what must we do if we are suspicious of a mast cell tumor?

Answer 20

diphenhydramine prior to poking

Question 21

What is the procedure to do a non aspiration fine needle biopsy?

Answer 21

1. secure mass w/ off hand, needle in dom hand
2. direct needle 5-6 times along same path into mass
3. Withdraw needle and attach to a 10ml air filled syringe
4. Expel sample onto slides

Question 22

Once sample is collected with a non-spiration method, what next?

Answer 22

use compression preparation, combination technique, or starfish smear to prepare sample
the needle may then be reinserted in another area of the mass and the process repeated to attain enough material to prepare more than one smear

Question 23

What is a tissue biopsy?

Answer 23

collecting a piece of tissue for either cytology, histology or both
tissue or organs may be biopsies and include various methods such as wedge biopsy or punch biopsy
can be done with the aid of ultrasound or endoscopy
skin biopsies should not be scrubbed or cleansed and any crusts, scales or surface debris should not be disturbed

Question 24

What is the wedge tissue biopsy?

Answer 24

use a scapel
advan: variable size specimen or the entire lesion
Always include a transition zone - normal tissue to transition to abnormal tissue

Question 25

What is the punch biopsy?

Answer 25

commonly used sizes 3, 4, 6 and 8mm cutaneous biopsy punch
3+4 don’t need suturing, but 6+8 will require one or two sutures

Question 26

How do we use a punch biopsy?

Answer 26

generally collect 3-4 biopsies of various lesions
use local anesthetic
gently press and rotate punch in one direction until lesion has been completely encircled
using fine forceps grasp tissue on its margins and place in 10% neutral phosphate-buffered formalin at 1:10 ratio of tissue to fixative

Question 27

What is the centesis collection method?

Answer 27

Inserting needle into body cavity/organ to remove fluid
abdominocentesis, thoracocentesis, arthrocentesis, and cystocentesis are most common
when collecting CSF, synovial fluid or fluids from eye, general anes is req

Question 28

How do you prepare a site for centesis?

Answer 28

surgical scrub or alcohol prep before beginning
Must follow strict aseptic technique to prevent a 2nd infection
a 21g needle is most commonly used to prevent cellular damage of sample and attached to a 20-60ml syringe - butterfly cath may also be used
record the total volume of fluid collected

Question 29

What do you need to do a thoracocentesis?

Answer 29

can use ultrasound guidance
needle inserted into 7th or 8th intercostal space
always use a 3-way stopcock
patient can be standing or in lat/sternal recumbency

Question 30

What do you need for an abdominocentesis?

Answer 30

needle into ventral abdomen approx. 1-2cm caudal to umbilicus
place either left or right of the midline depending on placement of patient
patient can be lat or standing

Question 31

What is a transtracheal/cronchial wash?

Answer 31

cells collected from trachea, bronchi, or bronchioles and assist w/ dx of pulomary dz
saline is infused @ rate of 0.5-1.0ml/kg of body weight thru a cath into trachea, bronchi or bronchioles
when patient coughs, plunger is pulled back several times to collect sample

Question 32

What happens once a sample is collected with transtracheal/bronchial wash?

Answer 32

a sm amount of saline that is infused is actually collected
low mucus samples should be centrifuged to concentrate the cells before making smears

Question 33

What are the 3 methods to collect a transtracheal/bronchial wash sample?

Answer 33

orotracheal, nasotracheal, transtracheal

Question 34

What is the procedure for doing a orotracheal wash?

Answer 34

cath placed thru ETT, patient is anesthetizes
preferred in small and fractious patients
patients do not cough with this technique so sample is withdrawn after a few seconds of insertion

Question 35

What is the procedure for doing a nasotracheal wash?

Answer 35

cath passed thru nasal passage, patient is sedated

Question 36

What is the transtracheal approach?

Answer 36

percutaneous approach (transtracheal): a cath is placed thru skin and trachea
patient is sedated
less contam from pharynx and nasal cavity
uses an 18-20g thru needle jugular catheter
requires a presurgical scrub and maintain aseptic technique

Question 37

Once any sample has been collected, what do we do?

Answer 37

Culture first when required
place on slide asap (if fluid, may need to spin down)
Always make at least 2 slides or more
stain/fix as needed - always leave at least one slide unstained
try to use more than one technique for making smears to maximize diagnostic potential

Question 38

How do we make a compression smear?

Answer 38

put sample on middle of slide
Place 2nd slide @ right angle on sample slide (like a t section)
quickly and smoothly slide across the sample slide
no downward pressure on sample slide - most common error is to rupture cells
modification is to rotate the spread slider 45 degrees and lift upward

Question 39

How do i make a combination technique?

Answer 39

place sample in middle of slide
take spreader slide, hold @ 45 angle
Pull spreader slide back unti makes contact w/ 1/3 of the sample
Essentially make a blood smear on one side, compression on the other
result is front 1/3 is gently spread
untouched n middle
Compression smare on back 1/3

Question 40

What is the starfish smear?

Answer 40

place sample on the sample slide
using the point of a sterile needle pull the sample in several directions away from the pool of sample
best used for fragile samples or viscous samples - ex. synovial fluid
make a star with it

Question 41

What must we do with samples taken from fluid?

Answer 41

prepare immediately after fluid collection
EDTA should be filled first and smears made
smears can be a compression, blood or line smear

Question 42

What is a line smear?

Answer 42

best used for samples w/ low cellularity as it concentrates the cells
place a drop of fluid on the slide near the frosted edge
take spreader slide, hold @ 30-45 angle to sample slide
pull spreader slide back until it makes contact w/ middle of the sample
slide spreader slide forward in a smoother and rapid motion
as you get 3/4 thru spreading the smear lift slide directly up

Question 43

How do we properly label slides?

Answer 43

be sure your requisition form is filled out correctly
slides need to be labelled w/ pencil and include patients ID (name, owner’s last name), site the sample was taken from, date

Question 44

What is more important, rods or cocci?

Answer 44

RODS