CYT 2113 Cytology I

Lesson 9:

Basic Gynecological Cytology

Pap Test

Part of a gynecological exam

An examination under the microscope of cells

scraped from the tip of the cervix

Features to be Evaluated in a Pap test

Adequacy

Presence of abnormal cells

Number and distribution of abnormal cells

Relationship between cells Relationship between cells

Cell size and shape

Nuclear size and shape

Nuclear changes and nucleoli

Nuclear-to-cytoplasmic (n:c) ratio

Cytoplasmic features Cytoplasmic features

Background or diathesis

Features of Preneoplastic and

Neoplastic cells

Abnormality in size and shape of cells

Variation in cell size and shape

Increase in nuclear size Increase in nuclear size

Increase in nuclear membrane irregularity

Hyperchromasia

Prominence of nucleoli and irregularity in

shape thereof

Thickening of nuclear membrane Thickening of nuclear membrane

Increase in n:c ratio

Cytoplasm scanty

Mitosis, increased number and abnormal

forms

Noncohesiveness Noncohesiveness

Common Causes of False-negative

Pap test

Atypical endocervical cells

Crowded cell aggregates

Cytolysis

Intermediate cells with nuclear enlargement Intermediate cells with nuclear enlargement

Metaplastic-like cells

Necrotic debris

Artifacts such as obscuring blood,

inflammation or air-dryinginflammation or air-drying

Common causes of false-positive

Pap test

Atrophic smear

Atypical endocervical or endometrial cells

Multinucleated cells

Perinuclear halo in nonkoilocytes

Reactive/repair

Squamous metaplasia

Tubal metaplasia

Differential diagnosis of cells with

naked nuclei

Naked nucleus - A nucleus in a cytologic

preparation that is virtually devoid of

cytoplasm

Autolysis of cytoplasm in menopause

Cytolysis

Degeneration, especially of endocervix

Reserve cells with tamoxifen treatment

Differential diagnosis of giant

multinucleated cells

Histiocytes

Atrophy

Folic acid deficiency

Tissue repair

Viral infection

Granuloma

Radiation Radiation

Syncytiotrophoblast (the outer syncytial layer

of the trophoblast that actively invades the

uterine wall forming the outermost fetal

component of the placenta)

Squamous carcinoma

Choriocarcinoma

Uterine sarcoma

Cytological features of dark-cell

clusters

Crowded with piling up of cells

Hyperchromatic overlapping nuclei

Anisonucleosis

Scant cytoplasm Scant cytoplasm

Increased n:c ratio

Mitosis present

Often difficult to determine whether

squamous or glandular

Differential diagnosis of dark-cell

clusters

Reactive endocervical cells

Tubal metaplasia

Atrophy: nuclear membrane smooth

Benign endometrial cells Benign endometrial cells

Atypical squamous cells cannot exclude high-

grade squamous intra-epithelial lesion

High-grade squamous intra-epithelial lesion:

nuclear membrane irregularnuclear membrane irregular

Adenocarcinoma in situ

Endocervical or endometrial carcinoma

Differential diagnosis of small cells

Lymphocytes in chronic lymphocytic cervicitis

Degenerated cells

Endometrial cells

Histiocytes Histiocytes

Reserve cells

Tamoxifen cells

Smaller cell type of squamous-cell carcinoma

Small-cell anaplastic carcinoma

Differential diagnosis of cells with

macronucleoli

Repair, regenerative or reactive squamous

cells

Reactive endocervical cells

Viral inclusions Viral inclusions

Treatment effect

Adenocarcinoma

Metastatic tumour

Nonkeratinizing squamous carcinoma

Differential diagnosis of

adenocarcinoma

Viral infections

Endocervical cells, benign and atypical

Endometrial cells, benign and atypical

Endometritis Endometritis

Histiocytes

Metaplasia

Vaginal adenosis

Intrauterine device

Metastatic tumour Metastatic tumour

Factors Related to Failure of Pap

Test Screening

Patient

Clinician

Instrument and sample

Cytopreparation and interpretation Cytopreparation and interpretation

Lesion

These factors are interrelated

Patient-related Errors

Including failure of women to get regular Pap

tests or to seek any health care at all

Douching or sexual intercourse can

mechanically remove the superficial cell layers

that the Pap test samples, causing false-that the Pap test samples, causing false-

negative results due to sampling error

Some women delay seeking medical attention

even when they have symptoms that they

know are suspicious, such as abnormal vaginal

bleeding

Clinical Errors

Failure to take a Pap test at all

Failure to take an adequate Pap test

The sample must be obtained under direct

visualization, with considerable pressure

The speculum should not be lubricated The speculum should not be lubricated

excessively

Overzealous rubbing, swabbing or cleaning

the cervix before taking the sample can

remove the abnormal cells, leading to false

negative results

Well-trained health care providers, not

necessarily physicians, take better Pap tests

Failure of the clinician to provide pertinent

clinical data can severely compromise

cytologic interpretation of the Pap test

Failure to follow-up abnormal Pap test results

Failure to perform a biopsy of suspicious

lesion

Failure to investigate suspicious clinical

symptoms

Instrument and Sample Errors

A combination of spatula and brush enhances

sampling compared with either device used

alone

The material from which the sampling device The material from which the sampling device

is important

Cotton swabs and wooden spatulas tend to

trap cells so they unavailable for

interpretation

Wooden spatulas collect between 600,000

and 1.2 million epithelial cells, but less than

20% are transferred to the glass slide when

making a conventional Pap smear

The transfer of cells to the slides is random

and statistically prone to error because the and statistically prone to error because the

abnormal cells are not homogenously

distributed in the sample

Endocervical samples taken by cotton swabs

or with plastic spatulas obtain fewer atypical

cells than do endocervical brushes

The shape of the sampling device is also

important for obtaining an adequate sample,

particularly of the endocervix

Sufficient numbers of well-preserved cells

must be collected and the sample must be

representative, including the transformation representative, including the transformation

zone

A conventional Pap smear must be thinly

spread and immediately and properly fixed

Cytopreparation and Interpretive

Errors

Few abnormal cells (particularly

Lesion-related Errors

Some lesions fail to exfoliate sufficient

numbers of cells for detection

Small or inaccessible lesions may be difficult

to sample adequatelyto sample adequately

The shape of the cells and the quality of the

cervical mucus also affect the sampling

Pap tests are more often inadequate in

women with advanced epithelial

abnormalities

Necrosis, inflammation or bleeding may

obscure, alter or dilute the abnormal cells,

making interpretation difficult

Pap tests repeated within a short time (up to Pap tests repeated within a short time (up to

several weeks) have a particularly high false

negative rate

Apparently it takes some time for the lesion to

regenerate sufficient cells to be detected in

the cytologic sample

A negative following a positive

interpretation can mislead the clinician into

thinking the lesion has regressed or the

previous positive report was wrongprevious positive report was wrong

It is also possible that some tumours progress

so rapidly that they develop in between Pap

test screenings