Fundamentals of cytological diagnostics and material sampling
Cytological examination relies on a detailed microscopic analysis of cellular material obtained from the patient. A cytopathologist identifies the pathological process based on three key diagnostic criteria:
- Morphological features of cells — changes in the shape, size, contours, and internal structure of individual cellular elements are evaluated.
- Quantitative ratio — proportions between various cell groups in the studied sample are analyzed.
- Arrangement of cellular elements — the way cells group together, whether they form clusters, and how they are distributed in the prepared specimen are examined.
To perform a comprehensive analysis in gynecology, various types of biological material are used, the choice of which depends on the clinical situation:
- Smears obtained directly from the surface of the cervix.
- Aspirate retrieved from the uterine cavity.
- Puncture fluid — this can be fluid obtained from the rectouterine pouch (cul-de-sac) or the contents of various pelvic masses.
The clinical significance of this diagnostic method cannot be overstated. It is the baseline screening method during mass preventive examinations of women. Special attention during screening is paid to patients at high risk for oncological diseases. However, the method has a significant drawback that physicians always keep in mind: its sensitivity is limited and amounts to only 60–70%.
Evaluation of cervical smear results (Papanicolaou system)
In the Russian Federation, specialists often use a standardized descriptive report when evaluating smears. Nevertheless, the most widespread, convenient, and universally accepted classification worldwide remains the Papanicolaou system, widely known as the Pap test. This system divides all possible cytological changes into five sequential classes, helping the physician quickly assess the severity of the process:
- Class I — absolutely normal cytological picture, no pathological changes in cells detected.
- Class II — reactive or inflammatory changes are present in epithelial cells.
- Class III — atypia of individual epithelial cells is detected. This condition raises suspicion of dysplasia.
- Class IV — isolated cells with clear malignant features are found in the specimen, raising suspicion of cancer.
- Class V — entire clusters of cells with pronounced malignant features are identified, which is a direct indication of cervical cancer.
Tissue biopsy as a confirmatory diagnostic method
Since cytology has insufficient sensitivity and serves only as a screening stage, when a malignant tumor of the cervix, vagina, external genitalia, and other structures is suspected, a biopsy is performed. A biopsy involves the in vivo acquisition of a small volume of tissue for subsequent deep microscopic examination to establish a definitive diagnosis.
In gynecological practice, depending on the localization and nature of the pathology, the following types of biopsy are used:
- Excisional biopsy — surgical excision of a small piece of suspicious tissue for analysis.
- Targeted biopsy — material sampling performed under direct visual control by a physician. Expanded colposcopy or hysteroscopy is used to ensure precision.
- Punch / needle biopsy — obtaining a tissue core or cellular material using a specialized needle.
Pap test classes are easy to remember by increasing severity: I — Normal, II — Inflammation, III — Dysplasia (atypia), IV — Isolated cancer cells, V — Cancer cell clusters.
Class and exam questions
What is the main difference between cytological examination and biopsy?
Cytological diagnostics studies the structural features of individual cells and their clusters in smears, aspirates, or puncture fluids. Biopsy, on the other hand, involves the in vivo acquisition of an entire small tissue volume to study its complete architecture.
Why doesn't a cytological smear provide a 100% guarantee that disease is absent?
The main drawback of the cytological method lies in its insufficient sensitivity, which is only 60–70%. This is precisely why it is used exclusively as a screening method during mass routine examinations rather than as a final diagnostic criterion.
What does Class III in the Papanicolaou system mean, and what are the next steps?
Class III in the Pap test indicates the presence of atypia in individual epithelial cells, raising the physician's suspicion of dysplasia. In such cases, further evaluation is required, most commonly including a targeted or excisional biopsy.
What else to study on this topic
- Technique of excisional and needle biopsy
- Visual control: expanded colposcopy and hysteroscopy
- Guidelines for obtaining fluid from the rectouterine pouch
- Features of obtaining an aspirate from the uterine cavity
- Descriptive cytological report in the practice of the Russian Federation
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