Cervical cytology

Author: Mikael Häggström

Magnification

While being fairly new to cervical cytology, preferably start looking at a high magnification such as 20x objective (with 10x eye piece). For suspicious findings, you may magnify up to maximum. On the other hand, once the pattern feels repetitive you can try switching to a slightly lower magnification such as 10x.

Adequacy

Adequacy should always be stated, either as "Satisfactory" or "Unsatisfactory". For estimating the number of cells, determine the following:

• The area of your field of view at high power (see the Evaluation chapter)
• The total size of the relevant area on the microscope slide. A ThinPrep is about 360 mm².
• Look at 10 representative high power fields (HPFs) within that area, and calculate the average number of cells per high power field.

Total number of cells = Average number of cells per HPF *

Total size of area HPF area

HPF example on a ThinPrep (about 360 mm²). If 10 fields gives a total of 40 cells, it will be 4 cells per HPF. The area of this field is 0.23 mm². hence, total cellularity is estimated to be:
4 cells * 360mm² / 0.23² = 6260 cells.

Conventional smear cellularity should be at least 8,000 cells. Liquid-based cytology cellularity should be at least 5,000 cells. Also a conventional smear is inadequate if >75% of cells are obscured by blood, exudate or air-drying artefact.

• Endocervical cells can be viewed from the side as nuclear polarity (margination towards the same side as others) in a “picket-fence” configuration.
  Endocervical cells can be viewed from the side as nuclear polarity (margination towards the same side as others) in a “picket-fence” configuration.
• 
  Sheets of endocervical cells have a honeycomb pattern.

Very common findings

• Bacterial flora (usually rod-shaped Lactobacilli), does not need reporting
  Bacterial flora (usually rod-shaped Lactobacilli), does not need reporting
• A clue cell, covered in bacteria, as compared to an unremarkable squamous cell at bottom left, and a neutrophil at bottom center. Pap stain. A significant amount of clue cells can be reported as "Shift in vaginal flora suggestive of bacterial vaginosis".
  A clue cell, covered in bacteria, as compared to an unremarkable squamous cell at bottom left, and a neutrophil at bottom center. Pap stain. A significant amount of clue cells can be reported as "Shift in vaginal flora suggestive of bacterial vaginosis".

Main conditions to exclude or confirm

Squamous atypia, seen mainly as cells with increased nucleus/cytoplasm ratio, nuclear hyperchromasia and irregular nuclear outline.

• Atypical squamous cells of undetermined significance (ASCUS), with only few slightly atypical cells
  Atypical squamous cells of undetermined significance (ASCUS), with only few slightly atypical cells
• Low-grade squamous intraepithelial lesion (LSIL), here compared to an unremarkable intermediate squamous cell.
  Low-grade squamous intraepithelial lesion (LSIL), here compared to an unremarkable intermediate squamous cell.
• 
  High-grade squamous intraepithelial lesion (HSIL), showing even more prominent features, and decreased cytoplasm, causing a high nuclear/cytoplasmic ratio.

Other findings

• Chlamydia trachomatis, with granular cytoplasm with multiple intracytoplasmic inclusions with central small coccoid bodies.
  Chlamydia trachomatis, with granular cytoplasm with multiple intracytoplasmic inclusions with central small coccoid bodies.

Report

Example in a normal case:

Cervical/endocervical ThinPrep: Negative for intraepithelial lesion or malignancy (NILM).

Main page

• Main page of Patholines