The Exfoliative cytology is the taking of samples for studies of any tissue through the "scraping" of it. Despite some controversies related to the fidelity of the samples and the definitive 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..
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..
Although oncology specialties have taken over the majority of exfoliative cytology procedures, other areas of medicine find utility in it.
Dermatologists, gynecologists, ophthalmologists, otolaryngologists and even dentists use these techniques very frequently to establish diagnoses and treatments..
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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 specific 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 obvious suppuration.
- That is vesicular type.
If specialists in the area have decided that exfoliative cytology is suitable for the study they want to perform, they can do it by following one of the following techniques:
This technique is carried out using a tongue depressor 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 are 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 tongue depressor but with greater precision. Whichever instrument is chosen, this technique is usually applied to 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.
As the name implies, this method is used for wet or suppurative lesion specimens. 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 samples of various mucous membranes, 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 these types of studies.
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 infections.
Common transparent tape is used. While some authors recommend a specific brand for its proven origin, others have been used with a comparable success rate.
The technique is very simple, just take a piece of tape and apply it directly to the lesion for a few seconds and then stick to a slide.
One peculiarity of tape cytology is that it is widely used in veterinary dermatology. Its usefulness for diagnosing skin diseases in dogs, cats, horses and cattle has made it a daily practice in animal consultations.
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 too 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 imprecise. One of the most important criticisms that this technique receives is its low specificity, being able to be confused between several pathologies or even not providing any information even when there is indeed a disease.
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..
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 most diagnosed oncological pathology with this technique.
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.
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..
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