Cytology of the vaginal smear

Cytology of the vaginal smear

Cytological examination of the vaginal smear is performed to evaluate the function of the ovaries. Depending on the ratio of cells of different layers of the epithelium, 4 types of cellular reactions are distinguished in smears, which allow to judge the functional state of the ovaries.

• I type. Smears that reflect a significant estrogen deficiency consist of basal cells with large nuclei and leukocytes; cells of the overlying layers are absent.
• II type. With an average degree of estrogen deficiency in smears, parabasal cells with large nuclei are predominantly determined; leukocytes are either absent or few; there may be basal and intermediate cells.
• III type. With a slight estrogen deficiency in the smear, the cells of the intermediate layer with medium nuclei, single surface cells and basal layer cells are mainly contained.
• IV type. With sufficient estrogen secretion, the smear consists of surface epithelial cells.

In clinical practice, smears can not always be attributed strictly to this or that type. Sometimes there are mixed patterns that are classified as intermediate types. In addition, the type of smear depends on the phase of the menstrual cycle. In the normal ovarian-menstrual cycle, during the proliferation phase, type III of the smear is observed, and during the ovulation period, III or IV type.

Investigation of the vaginal smear to resolve the issue of the functional status of the ovaries can not be performed with inflammatory discharge, after vaginal manipulation and with intravaginal administration of drugs.

To more accurately assess the hormonal stimulation by the cytological method, the following indices are used.

• Karyopicnotic index (KPI) is the ratio of surface cells with pycnotic nuclei (less than 5 μm) to surface cells with nuclei more than 6 μm. With a normal reaction of the pH of the vagina, the KPI value (%) strictly depends on the phase of the ovulatory menstrual cycle.

KPI indicators during the ovulatory menstrual cycle

	Menstrual cycle days
	-10-8	-6-4	-2-0	+2 - (+ 4)	+6 - (+ 8)	+10 - (+ 12)
KPI,%	20-40	50-70	80-88	60-40	30-25	25-20

• Atrophic index is the ratio of the number of cells of deep layers (basal and parabasal) to the total number of cells.
• The index of intermediate cells is the ratio of the number of intermediate cells to the total number of cells in the smear.
• Eosinophilic index (acidophilic) - the ratio of surface acidophilic cells to surface basophilic cells. The stronger the estrogenic stimulation, the more it appears in the smears of superficial eosinophilic-staining cells.
• The index of maturation is a differentiated count of cellular populations, expressed as a percentage. When calculating the maturation index, the smear should include only loose cells with normal morphology. The higher the degree of maturation of the epithelium, the more in the smears of cells with a high maturation index and the higher will be the total amount obtained when calculating the cellular composition of the smear.

To deduce the indices, consider at least 200 cells. The result is expressed as a percentage. The most important is KPI, the indicators of which more closely coincide with the level of hormone release. During the normal menstrual cycle, CRI changes as follows: during menstruation to 80-88%, in the progesterone phase to 20%; in the luteal phase up to 20-25%, that is, it is the maximum for IV type of vaginal smears.

The atrophic index is high (50-100%) for types I and II of the vaginal smears; the index of intermediate cells reaches 50-75% for types II and III, and the rise of the eosinophilic index (up to 70%) is observed during ovulation.

Scheme Vidal for the evaluation of the colpocytogram

Type of cell responses	Index of the vaginal epithelium,%
	Atrophic	Intermediate cells	Karyopicnotic
I	100	0	0
I-II	75	25	0
II	50	50	0
II-III	25	75	0
III	0	75	25
III-IV	0	75-50	25-50
IV	0	50-25	50-75

It should be noted that recently the cytological method of assessing the function of the ovaries is replaced by the determination of the concentration of sex hormones in the blood.

In addition to assessing the functional status of the ovaries, cytological examination of swabs from the vagina is important for identifying atypical cells. Signs of the latter include: polymorphism of cells and their nuclei, pronounced anisochromia of the cytoplasm, nuclei, an increase in the nuclear-cytoplasmic index, uneven, rough distribution of chromatin in cells, an increase in the number of nucleoli, and the detection of figures of mitotic division. The formulation of a cytological conclusion is important for a correct assessment by clinicians of the data obtained. The most widespread in the world was the classification of cytological findings of the Pap smear. It includes 5 groups.

• I group - there are no atypical cells. A normal cytological picture that does not cause suspicion.
• II group - a change in the morphology of cellular elements due to inflammation.
• III group - there are single cells with anomalies of the cytoplasm and nuclei, but the final diagnosis can not be established. It is necessary to repeat cytological examination, on the recommendation - histological.
• IV group - detect individual cells with obvious signs of malignancy: abnormal cytoplasm, altered nuclei, chromatin aberrations, increase in the mass of nuclei.
• V group - in smears there is a large number of typical cancer cells. The diagnosis of malignant process is beyond doubt.

[1], [2], [3], [4], [5]