Cytology and Cytological Techniques - PowerPoint PPT Presentation

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Cytology and Cytological Techniques

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Cytology and Cytological Techniques Clinical Pathology Cytology The microscopic examination of cells. Generally refers primarily to cells exfoliated from tissues ... – PowerPoint PPT presentation

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Title: Cytology and Cytological Techniques


1
Cytology and Cytological Techniques
  • Clinical Pathology

2
Cytology
  • The microscopic examination of cells.
  • Generally refers primarily to cells exfoliated
    from tissues, lesions, and internal organ/tumor
    cells.
  • A very valuable diagnostic tool.
  • Is inexpensive
  • Is quick and easy
  • Involves little or no risk to the patient

3
Cytology Continued
  • Must be able to identify normal cells from
    abnormal cells, and inflammatory from
    non-inflammatory cells
  • Disadvantage may be that some tumors do not
    exfoliate cells well and therefore may not
    provide and adequate sample to examine.

4
Cytologic Interpretation
  • May be able to diagnose
  • Identify the disease process
  • Help form a prognosis
  • May determine what diagnostic procedures should
    be performed next
  • May help with therapy options

5
Cytologic Techniques
  • Fine Needle Aspirate (FNA)
  • Fluid Aspiration- Thoracocentesis/Abdominocentesis
  • Solid mass imprinting
  • Vaginal wall technique
  • Cerebrospinal (CSF) Fluid Analysis
  • Synovial Fluid Analysis
  • Nasal Flush

6
General Collection Techniques
  • When possible prepare several smears
  • Use stained and unstained techniques
  • May use a variety of stains
  • Use clean, dry slides

7
Scrapings
  • Done on freshly cut surfaces
  • Scrap lesion/tissue with clean scalpel blade
  • Place material collected on a slide and spread
  • Advantage May collect more cells
  • Disadvantage More difficult to collect and only
    able to collect superficial lesions

8
Imprints
  • May be prepared from external lesions (ulcers)
  • May be prepared from tissues excised during
    surgery or necropsy.
  • Easy to collect
  • Disadvantage May only collect few cells and may
    contain contamination

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10
Solid Mass imprints
  • Cut mass in half
  • Blot dry
  • Need to remove blood/tissue fluid from surface
  • Use sterile gauze or other absorbent material
  • Excess blood/fluid inhibits cells from spreading
    and assuming normal size and shape
  • Touch the slide to the blotted surface
  • Stain

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12
Fine Needle Aspirates
  • Preferred method of obtaining samples from
    masses.
  • Avoids superficial contamination
  • Very little risk to patient
  • Less complications to internal organs than core
    biopsy techniques
  • Implantation of malignant cells along the
    aspiration tract is extremely rare
  • Disadvantage May not get a good sample because
    using just a small needle.

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14
Fine Needle Aspirate
  • 2 techniques
  • Aspiration
  • Collect with 22-25 gauge needle
  • Use 3-12 ml syringe
  • Need slides
  • Non-aspiration

15
FNA Aspiration Technique
  • Hold mass/lymph node firmly
  • Introduce the needle with syringe attached into
    the mass
  • Apply strong negative pressure by withdrawing the
    plunger to about 2/3 -3/4 of the volume.
  • Do several times in same area or redirect needle.
  • Stop negative pressure and remove needle from
    mass
  • Remove needle from syringe and air is drawn up
    into syringe
  • Sample that is in hub of needle is expelled onto
    slide by rapidly depressing the plunger
  • Hold needle close to slide, if too far away will
    result in small droplets that dry rapidly before
    smear technique may be done.

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18
FNA Non-Aspiration Technique
  • Works best for small masses that are difficult to
    aspirate.
  • Works well for highly vascular tissues
  • Using a needle only, move rapidly back and forth
    (stabbing motion).
  • Withdraw needle and place syringe with air to
    force onto slide.

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20
Preparation of smears from aspirates
  • Squash prep method
  • Needle spread method
  • Blood smear method

21
Squash Preparation
  • With experience, can yield excellent cytologic
    smears
  • Aspirated material is placed on the center of the
    slide
  • A second slide is placed over the sample to form
    a cross.
  • Carefully slide apart from first slide (Put down
    on and pick up to move).
  • Do not place excessive downward pressure to the
    first slide because will cause distorted ruptured
    cells
  • The weight of the spreader slide is sufficient to
    adequately spread the cells.

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23
Needle Spread Method
  • Spread aspirate on the slide with tip of needle.
  • Pull sample out into several projections
    (starfish appearance).

24
Blood Smear Technique
  • Use if material is thick or fluid
  • After material is expelled on slide, second slide
    is held at 30-40angle.
  • Second slide is pulled backward until it contacts
    the fluid
  • Rapidly move forward like a blood smear.

25
Common Problems with FNA
  • Few or no cells obtained
  • Some lesions do not exfoliate cells well.
  • The needle may miss the site of the lesion
  • Timid collection
  • Inadequate negative pressure
  • Blood contamination
  • Using too large needle gauge
  • Prolonged aspiration
  • Failure to blot if doing imprint

26
Common Problems with Preparation
  • Poorly prepared slides due to thick or high cell
    numbers
  • Allowing material to dry on slide before squash
    prep or other smear technique.
  • If a large amount of material is present, spread
    between two slides
  • May have to do 4-5 slides form the same site in
    order to get valuable diagnostic sample.

27
Staining Slides
  • Diff-quik, Wrights, Geimsa
  • Papanicolau stains-
  • used in human Ob/gyn exams. Stains nucleus and
    nuclear material better.
  • New Methylene Blue stain
  • Air dry these slides, do not heat fix.
  • Use clean slides (make sure no lint on slide)
  • Stain immediately after air drying
  • Take care not to touch the surface of the slide
    or smear at any time.

28
Medical Terminology
  • Hypertrophy-an increase in cell size and/or
    functional activity in response to a stimulus.
  • Hyperplasia- increase in cell numbers, via
    increased mitotic activity, in response to a
    stimulus.
  • Neoplasia- increase in cell growth and
    multiplication that is not dependent on an
    external stimulus.
  • Metaplasia- a reversible process in which one
    mature cell type is replaced by another mature
    cell type (adaptive response to a stimulus)

29
Medical Terminology Continued
  • Dysplasia- reversible, irregular, atypical,
    proliferative cellular changes in response to
    irritation or inflammation.
  • Anaplasia- A lack of differentiation of tissue
    cells
  • Less differentiated cells in a tumor is more
    malignant
  • Chromatin pattern- the microscopic pattern of
    nuclear chromatin (the chromatin pattern coarsens
    as malignant potential increases)
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