Evaluation

Author: Mikael Häggström

Main steps

• Preferably, look up past medical history of the patient, mainly past cancers that could possibly appear in the current specimen.
• Look at each microscopy slide by eye, to plan the microscopy screening so as to not miss peripheral fragments.
• Have a systematic direction of screening through microscopy slides, such as from top left to bottom right as seen in the microscope. When the microscope makes what you see two-way mirrored, the starting position is with the objective pointing at the bottom right of the glass slide.

• 
  Example starting position of objective.
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  Example slide scanning directions.

While learning, you will generally focus relatively more on high magnification features with high specificity, but still have a habit of learning how your cases look at low magnification as well. In time, you will increasingly correlate diseases and conditions with their overall low magnification patterns - patterns that may require 1000 words to describe and thus cannot conveniently be part of written criteria, but will nevertheless allow you to make quicker and more accurate diagnoses.

Condenser

Generally the condenser is placed in its highest position or just slightly lower. At low magnification objectives (mainly 4x and 10x objectives), the opening of the condenser (or iris) diaphragm should be wide open. For high-dry (40x) and oil-immersion objectives (100x), the diaphragm should be closed slowly while looking at a sharply focused section until the level of illumination is just slightly reduced, in order to attain optimal contrast and resolution.

Artifacts

In microscopy, an artifact is an apparent structural detail that is caused by the processing of the specimen and is thus not a legitimate feature of the specimen. Major artifacts to account for include:

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  Cellulose contamination, here seen on H&E stain and polarized light, respectively.
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  Cardiac muscle (bottom) with contamination from thyroid tissue (center).
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  Crush artifact from compression by forceps on the tissue sample.
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  Folding artifacts (white arrows) and a crush artifact (black arrow, with cytoplasmic hypereosinophilia and nuclear pleomorphism) from a needle.
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  Tearing artifacts, such as can be caused by:
  - Microtomy with a nick or blemish in the knife edge.
  - Traction of the sections.
  - Too much or too little alcohol dehydration.
  - Sectioning calcified parts, which can be decalcified or removed.
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  More tearing artifacts, showing that they may be more circular than fusiform.
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  'Formalin pigment artifacts
• Air bubble entrapment artifacts
  Air bubble entrapment artifacts
• Staining artifacts by residual wax, resulting in pale areas where cellular structures are not discernible.
  Staining artifacts by residual wax, resulting in pale areas where cellular structures are not discernible.
• A separation artifact in top image makes the tumor look incompletely excised, but the next microtomy level (bottom image) shows a surgical margin of connective tissue.
  A separation artifact in top image makes the tumor look incompletely excised, but the next microtomy level (bottom image) shows a surgical margin of connective tissue.

Inflammation

• Neutrophils generally confers a diagnosis of acute inflammation.
  Neutrophils generally confers a diagnosis of acute inflammation.
• Plasma cells and lymphocytes generally confers a diagnosis of chronic inflammation if present in increased amount for the location.
  Plasma cells and lymphocytes generally confers a diagnosis of chronic inflammation if present in increased amount for the location.
• However, disregard intravascular white blood cells.
  However, disregard intravascular white blood cells.

Main page

• Main page of Patholines