Cytology and Cytological Techniques

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Cytology and Cytological Techniques

• Clinical Pathology

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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

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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.

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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

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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

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General Collection Techniques

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

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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

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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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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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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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Fine Needle Aspirate

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

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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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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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Preparation of smears from aspirates

• Squash prep method
• Needle spread method
• Blood smear method

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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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Needle Spread Method

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

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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.

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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

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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.

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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.

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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)

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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)