cytology

Cytology

Study of cells individually or in a group

Histopathology

Microscopic study of disease in tissues

Exfoliative cytology

Study of cells shed from body tissues

Ex. Body fluids, mucosa, secretions

What are the variety of sources for exfoliative cytology

• csf

• Peritoneal

• Abdominal

• Thoracic

• Pericardial

• Pleural

• Synovial

• Tracheal

• Vagina

• Seen

• Prostatic fluid

• Milk

Preparation technique for histopathology

1. Sample is collected and immersed in fixative solution

2. Sample is dehydrated

3. Sample is embedded in paraffin wax block, then sliced into sections

4. A slice is mounted on glass slide, stained, then evaluated microscopically

Which techniques are used for solid mass samples

• swab, scrape, or imprint

• Fine needle aspirate or biopsy

Which techniques are used for fluid sample collection

• fine needle aspirate or biopsy

• Centesis

When are swabs done

Only when scrapings or imprints cannot be done

Pros and cons of scrapings

Pros: collects many cells from firm lesions

Cons: difficult to collect, only superficial cells, may reflect secondary bacterial infection or inflammation

Pros and cons of imprints

Pros: easy to colllect and minimal restraint needed

Cons: lot of contamination (bacterial and cellular), only reflects secondary infection or inflammation, may hinder neoplasia Dx

Pros and cons of FNA techniques

Pros: avoids superficial contamination from cutaneous lesions

Cons: poor yield of free cells if large needle used, more blood contamination

Difference between a general FNA procedure and the negative pressure procedure

FNA procedure - needle is redirected while in the mass

Negative pressure - needle is not redirected, just multiple pulses/aspirations of the syringe

Non-aspirate procedure

• no re-directing of the needle or pulling back of plunger

• Move needle rapidly back and forth along the same tract

• Collected by shearing and capillary action

What advantage does the punch biopsy have over a wedge biopsy

• ease and speed of procedure

• Different sizes of punch (3,4,6,8 mm disposable punches)

• Can perform with local anesthetic

Which tissue biopsy is done under heavy sedation or GA

Tru cut biopsy

Different sites for Centesis procedure

• Abdominocentesis

• Thoracocentesis

• Arthrocentesis

• Cystocentesis

What does ease of collection for a centesis depend on

• volume of fluid present

• Pressure within the body cavity

• Technical proficiency of operator

• Cooperation of anima,

What do you always record from a fluid sample

• volume collected

• Gross characteristics: colour and turbidity

What are colour and turbidity influenced by

• protein concentration

• Cell numbers

Technique for transtracheal wash

• fill lungs with fluid then suction it out

• Patient is anesthetized

• Done through and ET tube

• Minimizes pharyngeal contamination of specimen

What is BAL

Bronchoalveolar lavage

• specialized orotracheal technique

• Requires bronchoscopy

• Lower respiratory tract evaluated

Percutaneous technique

• clip hair and aseptically prepare the laryngeal area

• Use lidocaine for local anesthetic

• Needle is inserted into trachea, and catheter advanced into the lumen

• Sterile saline infused though catheter, when animal coughs pull plunger to collect fluid

Compression smears

Aka squash prep

• expel contents of aspirate onto the slide

• Spreader slide slides across the prep slide

For thicker tissue: rotate second slide instead of sliding

When would a Line smear be done

Used for low cellularity samples or small volume

• same as blood smear technique except spreader slide is raised straight upward to create a concentrated line of cells

What influences selection of smear technique for fluid samples

• cellularity

• Viscosity

• Homogeneity

Starfish smear

Drags aspirate peripherally in several directions with the point of a needle

• ideal for viscous samples

Wedge smear

Same as a blood smear

• creates a feathered edge

Why is fixing important

So you don’t loose your sample when staining it

• done is 95% methanol

What does the Romanowsky stains stain?

Organisms and cytoplasm

What does New Methylene Blue stain

Nucleus

How can we avoid staining problems

• use a new, clean slide every time

• Use fresh, well filtered stains

• Always fix the slides

• Do not touch the surface of the slides

• Avoid contamination with foreign substances

Where can bone marrow samples be collected from

Head of the femur or humerus

Main purpose of cytology evaluations

To differentiate between inflammation and neoplasia

4 different categories of inflammation

1. Suppurative (purulent)

2. Granulomatous

3. Pyrogranulomatous

4. Eosinophilic

What is suppurative inflammation

• pus

• Lots of neutrophils >85%

• Will be able to smell it

What is granulomatous/pyogranulomatous inflammation

• significant number of macrophages present

• >15%

• Fungal or parasitic infections manifest this way

What is eosinophilic inflammation

• usually found with parasitic infections

• >10% of eosinophils along with neutrophils

• Also found in neoplastic disorders

Karyolysis

Rapid cell death

Karryorrhexis

Cell fragmentation

Pyknosis

Slow cell death

• small, condensed, dark nucleus

Neoplasia

Contain a homogenous population of a single cell type

Benign cells

Usually same type and relatively uniform in appearance

Possible abnormalities of malignant cells (must have at least 3 to be malignant)

• anisokaryosis

• Pleomorphism

• Variable nucleus:cytoplasm ratio

• Increased mitotic activity

• Coarse chromatin pattern

• Nuclear molding

• Multinucleation

• Anisonucleosis

Epithelial cell tumor characteristics

• highly cellular

• Often exfoliate in clumps or sheets

• Called: carcinomas or adnocarcinomas

Mesenchymal cell tumors characteristics

• less cellular

• Cells exfoliate singly or in spindles

• Called sarcomas

Round cell tumor characteristics

• not in clumps or clusters

Ex. Mast cell tumors, Melanoma, Venereal tumor, Lymphoma

What is cornification

Slow coordinated process that allows formation of dead cell layer, to create a physical barrier for the skin and MM

• protective layer