Cytophysiologic changes in female genital tract

Menstrual phase

• 1st- 5th day

• Erythrocyte

• Leukocytes

• Endometrial cells

• Superficial and intermediate cells

Proliferative phase

• 6th-10th day

• mainly large and small basophilic (blue)

• Intermediate cells

• Leukocytes

• Histiocytes

• Endometrial cells

• Towards the end of follicular phase, number of superficial squamous cells increase

Ovulation phase

• Numerouus of superficial epithelial cells

• Cells lie flat and obviously discrete

• Pattern is clean without leukocytes

• Very few bacteria

• appear due to high estrogen levels

• Some smear, a fern pattern of the endocervical mucus can be discerned.

Secretory phase

• Day 15-22

• folded or with curled edges

• Appear immediately after ovulation due to increase in progesterone.

• Leukocytes (small black cells) becoming more numerous.

Late secretory phase

• Day 23rd -28th

• Intermediate cells predominate

• Clustering and folding of cells occurs at this stage and both leukocytes (neutrophil)and bacteria (Doderlin bacilli) are prevalent

Physiological changes of the female genital tract

There are a few phases in a women’s life which can influence the surroundings of the cervical area and more importantly the cells which predominates during those stages. The changes commonly occur during phases as below:-

i) Pregnancyii) Post-delivery and post-partumiii) Menopauseiv) Exogenous sex steroid

The aforementioned cytohormonal changes can be evaluated using hormonal evaluation. Hormonal evaluation is used in evaluating the hormonal status for monitoring pregnancy, determining timing of ovulation for fertility workup, and artificial insemination. Sequential smears are obtained to assess variability in pattern. A minimum of 100 cells are counted and the number of parabasal (P), intermediate(I), and a superficial(S) clls are expressed as a ration (P:I:S).

Pregnancy

Pregnancy constitutes a major physiologic upheaval in the life of a woman. This brief summary will stress those morphologic changes that may have an impact on cytology of the female genital tract. Cytologic manifestations of pregnancy:

i) Squamous cells: a. The effects on the squamous cell epithelium are frequently but not always

reflected in vaginal smears after the 2nd month. b. These changes are characterized by clustering of intermediate cells and the

predominance of intermediate squamous cells, the latter defined by yellow cytoplasmic deposits of glycogen, displacing the nuclei to the periphery, and sharply defined, accentuated borders.

c. In the later stages of pregnancy, extensive cytolysis of squamous cell cytoplasm by lactobacilli is not uncommon.

d. Majority of women show pattern of navicular cells but isn’t always diagnostic of pregnancy.

ii) Endocervical cells:a. May appear in somewhat increased number in cervical smears and may be larger

than normalb. Cytoplasm is often mucoid, and the nuclei are prominent, granular, and may

show small nucleoli.iii) Decidual cells:

a. Large mononucleated cells, occurring singly or in clusters, with abundant eosinophilic or basophilic faintly vacuolated cytoplasm and prominent, centrally-located vesicular nuclei containing identifiable nucleoli.

b. Occasionally, nuclei of decidual cells may be dense and hyperchromatic, particularly when derived from degenerating decidual tissue.

iv) Arias-Stella Phenomenon a. Large cells with large, hyperchromatic nuclei located within the endometrial

gland lining in the presence of products of conception or in ectopic pregnancy.b. Appear following curettage for interruption of pregnancy. c. Protruding large cells stand out among normal endometrial cells.d. Great variability of nuclear morphology.

Postpartum period

During the postpartum period, there is often no evidence of estrogen activity.

a) Many women display atrophic smear pattern with predominance of parabasal squamous cells.

b) During lactation, intermediate and large parabasal cells of navicular type, with large cytoplasmic glycogen deposits may be observed.

c) The return to cyclic patterns varies from patient. In the great majority of patients, whether lactating or not, the cyclic pattern will be evident 6 months after delivery.

d) Persistence of atrophic smear pattern, beyond 1 year after delivery, may indicate a serious endocrine disorder.

Abortion

The interruption of pregnancy prior to 20 weeks of gestation is referred to as abortion and it may be spontaneous or induced. Spontaneous abortion is classified as threatened, inevitable, incomplete and complete. Cytologic assessment of these conditions

should only be used an adjuvant to the more critical and reliable clinical and chemical evaluations.

i) Threatened abortion:a. Certain changes in the cytohormonal pattern may suggest that the patient is at

risk of aborting.b. The superficial cells increase in number >10% and the navicular cells gradually

disappear. c. This may reflect the relative dominance of estrogen and risk to the fetus.d. The development of postpartum pattern and the dominance of parabasal cells

may be associated with fetal demise.ii) Incomplete abortion:

a. Residual villi or deciduas can cause bleeding and infectionb. The smears contain blood, leukocytes, trophoblastic cells, and rarely, smooth

muscle cells.c. Isolated or clustered decidual cells with cobblestone squamoid appearance may

be present. If well preserved, these decidual cells have abundant eosinophilic or cynophilic cytoplasm.

d. Their nuclei have vesicular, finely granular, and uniformly distributed chromatin, and unlike squamous cells, they possess nucleoli. The thin but well-defined nuclear membrane may be wrinkled.

e. Exfoliated decidual cells, however, are usually degenerated with poor delineation of cytoplasmic borders and nuclear details.

iii) Spontaneous abortion a. Occur at about 12th week of gestation.b. The risk of abortion increases with age, parity, and the number of previous

abortions.c. Causes of spontaneous abortions are many and in a given case it’s difficult to

state the exact cause as several factors may be involved:i. Defective germ plasm: due to defective embryos. Closer examination of

the conceptus may reveal several developmental or structural anomalies in the embryo, defects in the placenta or in the cord.

ii. Maternal causes: infections such as rubella, CMV disease or toxoplasmosis. Syphilis is seldom responsible for the abortions in the first trimester.

iii. Endocrine deficiency of the thyroid or corpus luteum.iv. Anatomical defects: congenital uterine anomalies such as a bicornuate or

septate uterus, internal os insufficiency due to congenital or acquired causes.

v. Uterine myomatavi. Trauma, chemicals, radiation

vii. Immunological factorsviii. Maternal diseases like diabetes, systemic lupus erythematosus.

ix. Paternal cause: defective spermatozoa, however, there is not enough evidence in support.

Menopause

The menopause is caused by the cessation of cyclic ovarian function, resulting in the arrest of menstrual bleeding. The onset of the menopause is rarely sudden, the changes are usually gradual and may stretch over a period of several years, with gradual reduction in duration and frequency of the menstrual flow. The age at which complete menopause occurs varies. Clinical and cytologic menopause doesn’t necessarily coincide. The most important manifestation of the menopause is associated with reduced production of estrogen, although other complex changes in the endocrine balance are known to occur. The ovaries, the principal source of estrogen, become scarred and hyalinized without remaining evidence of ovogenic activity. Because of estrogenic deficiency, there is a cessation of endometrial proliferation with resulting endometrial atrophy. Gradual estrogen depletion will also result in gradual loss of superficial cell layers. In final stages of atrophy, the surface of squamous epithelium is composed of parabasal cells. Endocervical epithelium also shows evidence of atrophy; the columnar endocervical cells are often more cuboidal in shape, and their cytoplasm becomes opaque. Vaginal dryness is common in menopausal women; hence it causes a number of artifacts, similar to air drying of the smear. Dryness also offers little resistance to bacterial invasion, resulting in vaginitis and cervicitis.

There are 3 basic cytologic patterns of menopause which may be differentiated – early menopause, “crowded” menopause and advanced or atrophic menopause. A sharp separation of the 3 post-menopausal smear patterns isn’t always possible in practice, since one pattern may emerge into another.

i) Early menopause: slight deficiency of estrogensa. The smears are essentially those of childbearing age, except for a reduction in

the proportion of superficial squamous cells.b. Cells are composed predominantly of dispersed intermediate cells, occasionally

showing cytolysis, and some large parabasal cells. These cells contain vesicular nuclei of normal size, about 8 microns in diameter.

c. Nuclei may appear to be diffusely enlarged.

d. Women who lead an active sexual life after the menopause appear to be less likely to develop post-menopausal atrophy than sexually inactive women.

ii) “Crowded” menopause: moderate deficiency of estrogensa. This type of smear usually follows the smear of early menopause and

characterized by thick, crowded clusters of intermediate and large parabsal cellsb. Cells are well-preserved and there’s little drynessc. Small-sized-cells; thus nuclei may appear to be relatively large but are of normal

sizes.d. The cytoplasm frequently contains deposits of glycogen in the form of yellow

deposits, similar to navicular cells observed in pregnancy.iii) Atrophic or advanced menopause

a. May be invariably preceded by early or crowded menopause or both. There’s always a stage of transition between normal cycle and the advanced menopause.

Exogenous sex steroid

The vaginal epithelium can be influenced by the administration of exogenous hormones and drugs. The effects of these substances depend on the drug dosage, receptivity of the end organ, age of patient, and the initial hormonal status.

i) Estrogen

a) Administration of exogenous estrogen has no effect on the cytohormonal pattern of a normal pregnancy.

b) In post-menopausal women, exogenous estrogenic stimulation results in progressive maturation of epithelium.

c) Parabasal cell type atrophy changes into intermediate cell type, while the intermediate cell type atrophy matures to superficial cells if the hormone was given for a short period of 3-6 months. Administration for longer periods results in marked predominance of intermediate cells. Estrogen may be administered to clarify the nature of questionable or suspicious cells showing post-menopausal nuclear enlargement, or atypical immature cells.

d) It can also improve the cellularity and adequacy of sampling in some cases. A conjugated estrogen such as premarin or diethylstilbestrol is given orally, divided over 5 days, and a smear is obtained on day 7.

e) Alternatively, a single topical application of estrogen ointment or suppositories can be used, to be followed by smears in 3 days. Following this “estrogen test”, a normal smear is usually clean, with more superficial and intermediate cells.

ii) Exogenous progesterone, androgen

a. Has no effect on normal pregnancy, but can induce increased exfoliation of intermediate cells.

b. After menopause, the administration of progesterone may alter the parabasal cell pattern may alter the parabasal cell pattern to an intermediate cell pattern in some patients, while in others no change may occur.

c. The administration of androgens to postmenopausal patients doesn’t result in characteristic pattern. This effect may be similar to that of progesterone and may or may not alter the atrophic pattern.

d. In large doses, however, androgens can induce maturation to superficial cells. In younger patients, endogenous or exogenous androgens induce an atrophic pattern, with glycogen-rich parabasal cells.

e. Corticosteroids induce maturation of the cells to the intermediate cell level, followed by shedding of epithelium. This results in intermediate cell predominance or a spread effect. However, the intermediate cells don’t cluster or exhibit the folding of their edges that characterize progesterone effect.

iii) Oral contraceptives

These are the most commonly administered exogenous hormones and consist of a combination of estrogen and progesterone in various ratios. They are usually given in day 5 to 25 of the menstrual cycle and they are discontinued until the 5 th day of the next cycle. 3 types of combinations are used: a fixed combination of estrogen and progesterone, a biphasic one with more progesterone 3 types from day 11, and a triphasic combination, with a gradually increasing dosage of progesterone.