EXFOLIATIVE CYTOLOGY: TYPES, TECHNIQUES, ADVANTAGES AND USES - MEDICINE - 2025

The exfoliative cytology is the sampling for studies of any tissue through the "scraping" of the same . Despite some controversies related to the fidelity of the samples and the final results, this simple and practically painless procedure continues to be in vogue within the world of pathology.

The technique to perform exfoliative cytology is really simple. In fact, many times it is enough to pass a sterile swab over the area to be evaluated to obtain a quality sample.

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However, several ways to do this are described, depending on the part of the body to be evaluated and the presumptive diagnoses to rule out.

While oncology specialties have taken over the majority of exfoliative cytology procedures, other areas of medicine find use in it.

Dermatologists, gynecologists, ophthalmologists, otolaryngologists and even dentists use these techniques very frequently to establish diagnoses and treatments.

Techniques

The methods used to collect samples through exfoliation vary somewhat depending on the organ or tissue being studied and the medical specialty involved.

Despite this, most share certain characteristics such as the almost total absence of pain at the time of the procedure and its low specificity.

Three factors inherent to the lesion are important when determining whether or not an exfoliative cytology applies to take a tissue sample:

- That the lesion can come off when scraping.

- That is accompanied by evident suppuration.

- That is vesicular type.

If specialists in the area have decided that exfoliative cytology is suitable for the study they wish to perform, they can do it by following one of the following techniques:

Scraping cytology proper

This technique is carried out using a tongue blade or wooden or plastic trowel. The smooth edges of the selected equipment slide exerting a little pressure on the lesion, exerting the effect of scraping. Cellular debris that accumulates on the tongue blade or paddle is then transferred to a slide or test tube.

The back of a scalpel can also be used but not its cutting part. This blunt edge fulfills the same role as the slipper but with greater precision. Whichever instrument is chosen, this technique is usually applied in dry lesions and is almost exclusively used in skin lesions.

An exception to the above rule is samples taken from the cervix, which is wet. Two special instruments are used for these: an exocervical spatula that is used to take samples from the outside of the cervix and an endocervical brush that takes internal samples. This procedure is the Pap test.

Liquid cytology

As the name implies, this method is used for wet or suppurative lesion samples. The instrument par excellence for this technique is the cotton swab or applicator.

There are special swabs on the market that bring with them a culture medium where the sample is introduced immediately after being taken.

Another frequent use of this technique is the taking of various mucosa samples, such as oral, pharyngeal, nasal, rectal or urethral, ​​without the need for obvious lesions.

Many oncological or infectious diseases can be detected before they are symptomatic or in early stages thanks to this type of study.

Tape cytology

This type of exfoliative cytology is usually performed on regular and dry skin lesions, with a lot of flaking but at the same time very friable.

When scraping exfoliation can cause bleeding or ulcers, this method is preferred, which does not produce added lesions and reduces the risk of infection.

Common transparent tape is used. While some authors recommend a specific brand because of its proven origin, others have been used with a comparable success rate.

The technique is very simple, you just take a piece of tape and apply it directly to the injury for a few seconds and then stick it to a slide.

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One particularity of tape cytology is that it is widely used in veterinary dermatology. Its usefulness in diagnosing skin diseases in dogs, cats, horses and cattle has made it a daily practice in animal consultations.

Advantages and disadvantages

Exfoliative cytology, like any medical procedure, has its advantages and disadvantages. One of the benefits of exfoliative cytology is how easy it is to perform.

The different techniques to carry them out are easy to apply and learn, not requiring much training to be successful.

They also tend to be painless. They rarely cause significant discomfort or the need for local anesthesia. Another advantage is the immediacy of the results. Many times the sample taken can be stained with special dyes and evaluated under a microscope to obtain a diagnosis.

Unfortunately exfoliative cytology can be inaccurate. One of the most important criticisms of this technique is its low specificity, which can be confused between various pathologies or even not provide any information even when there is indeed a disease.

Applications

Exfoliative cytology has purely diagnostic functions. Its task is to help the clinician to detect which disease an individual is suffering from in order to initiate treatment.

Unlike other pathological studies in which larger pieces are removed, this type of cytology will never be curative.

Oncology

Cancer detection is one of the main goals of exfoliative cytology. Wherever samples are taken and through any of the techniques described, it is possible to find malignant cells at different stages of their development. Cervical cancer is the cancer pathology most diagnosed with this technique.

Dermatology

Many skin diseases are diagnosed with exfoliative cytology samples. After gynecological diseases, skin pathologies are the most frequently encountered thanks to this method. Most of these are autoimmune and inflammatory processes.

Infectology

Certain infectious processes of the skin, eyes, mouth, throat and genitourinary tract can be discovered through cultures of samples obtained by exfoliative cytology.

Even some parasites, especially perianal, are detected by the transparent adhesive tape technique.

References

1. Shaila M, Shetty P, Pai P. A new approach to exfoliative cytology: A comparative cytomorphometric study. Indian Journal of Cancer. 2016; 53 (1): 193-198. Available at indianjcancer.com/
2. Ramakrishnaiah VP, Babu R, Pai D, Verma SK. Role of imprint / exfoliative cytology in ulcerated skin neoplasms. Indian Journal of Surgical Oncology. 2013; 4 (4): 385-9. Available at ncbi.nlm.nih.gov/
3. Al-Abbadi MA. Basics of Cytology. Avicenna Journal of Medicine. 2011; 1 (1): 18-28. Available at ncbi.nlm.nih.gov/
4. Acha A, Ruesga MT, Rodríguez MJ, Martínez de Pancorbo MA, Aguirre JM. Applications of oral scraping cytology (exfoliative) in oral cancer and precancer. Oral Medicine and Pathology. 2005; 10: 95-102. Available at Medicinaoral.com/
5. Gomes CA, Catapani WR, Mader AM, Locatelli A, Silva CB, Waisberg J. Antral exfoliative cytology for the detection of Helicobacter pylori in the stomach. World Journal of Gastroenterology. 2005; 11 (18): 2784-8. Available at wjgnet.com/
6. Marchand L, Mundt M, Klein G, Agarwal SC. Optimal collection technique and devices for a quality pap smear. Wisconsin Medical Journal. 2005; 104 (6): 51-55. Available at wisconsinmedicalsociety.org/
7. Bajwa J. Cutaneous cytology and the dermatology patient. The Canadian Veterinary Journal. 2017; 58 (6): 625-627. Available at ncbi.nlm.nih.gov/