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An Official Publication of the Indian Association of Oral and Maxillofacial Pathologists


 
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Year : 2004  |  Volume : 8  |  Issue : 2  |  Page : 54-57
 

Yet another article on exfoliative cytology


Department of Oral and Maxillo Facial Pathology, Meenakshi Ammal Dental College and Hospital, Chennai, India

Correspondence Address:
B Sivapathasundharam
Department of OMFP, Meenakshi Ammal Dental College and Hospital, Alapakkam Road, Maduravoyal, Chennai 600 095
India
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Source of Support: None, Conflict of Interest: None


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How to cite this article:
Sivapathasundharam B, Kalasagar M. Yet another article on exfoliative cytology. J Oral Maxillofac Pathol 2004;8:54-7

How to cite this URL:
Sivapathasundharam B, Kalasagar M. Yet another article on exfoliative cytology. J Oral Maxillofac Pathol [serial online] 2004 [cited 2019 Aug 22];8:54-7. Available from: http://www.jomfp.in/text.asp?2004/8/2/54/40967



   Introduction Top


Why spend another bunch of papers of a leading dental periodical; spend even 5-10 minutes reading about the same old technique of scraping, spreading, staining and seeing in the microscope, only to send for a confirmation by biopsy?

The understanding and application of exfoliative cytology techniques in the stomatology clinics in India is sporadic, particularly, for the purpose of diagnostics unlike our counter parts in the developed countries. More papers on exfoliative cytology were published during the period 1955-75 than in any other period [1] . Renewed interest emerged in the past decade after the employment of newer techniques of quantitative analysis, DNA cytomorphometry, identification of tumour markers on the cytological samples and the like.


   Definition Top


Exfoliative cytology is the microscopic examination of shed or desquamated cells from the epithelial surface usually the mucous membrane. It also includes the study of those cells that have been collected by scraping the tissue surface or collected from body fluids such as sputum, saliva, etc [2] .

This definition can be comfortably adopted as it unifies the redundant and more confusing terms like 'abrasive' and 'desquamative' under a single umbrella "the exfoliative cytology".


   Historical Evolution Top
[3]

The available literature suggests that Walsh was the first person to have described cancer cells in a patient's sputum as early as in 1843.

Lebert in 1851 emphasized the altered size of cells and nuclei as a basis of diagnosing cancer. Bealem 1960 attempted a cytological diagnosis of oropharyngeal cancer. Dudgeon in1927 devised a direct smear technique of surgical specimen for rapid diagnosis.

In the year l941 [4] George N Papanicolaou started using what is today called as "PAP test" as a routine procedure for early detection.

Ziskin was the first person to have reported the use of exfoliative cytology in oral cavity. Montgomery and Von Hamm in1951 used exfoliative cytology for the diagnosis of oral cancer.


   Rationale of Exfoliative Cytology Top


Rationale of exfoliative cytology lies in the epithelial physiology. Continuous exfoliation of epithelial cells is a part of physiological turnover. Deeper cells, which are strongly adhered in normal conditions, become loose in the case of malignancy and exfoliate along with superficial cells.


   Technique Top
[4]

Conventionally wooden spatula scrapings of buccal mucosa was a favorite, but due to the pressure on the cells, and folding and alteration of cytoplasm during smearing, a cytobrush is now a preferred device.

Henry Sandler [4] reviewed various other techniques which included cotton tip applicators, vigorous normal saline rinse, forceful aspiration of cells from the surface, aspiration of resting saliva from the floor, etc, and discussed the pros and cons of each.

A monolayer of cells is desired after a smear preparation which is attained after a minimal experience. PAP is still a big hit in the cytology staining procedures.


   Why PAP After All? Top


The advantages of PAP staining lies in the fact that the dehydration and clearing solutions help in causing cellular transparency. This detects the overlapped cells and their individual morphology better, which otherwise would be confused for a giant cell, or a bi or multinucleated cell. The second significant advantage is the differential staining for different degrees of differentiation, green-blue cytoplasm for basal cells and yellow-orange for a spinous or granular cell.

Then again like some other techniques of good standing we do have a stability of stains over long periods, stability of colour and of course the better reproducibility of results.


   Interpretation Top


A different outlook has been attempted in this review in the interpretation and understanding of an exfoliated cell, concentrating more on a correlation with the cell physiology along the sidelines.

The basic defect of any cell alteration begins at the molecular level triggering a series of reactions and thereby affecting the entire cell system and consequently its morphology.

In short, the cellular morphology bespeaks the biological activity. But ironically, a myriad of influences on a cell produces only limited morphological responses thereby challenging the human brain in every smear that is taken. Conversely, this is giving an edge for the real human intelligence over the fast emerging world of virtual intelligence extending its tentacles into every known arena.

John K Frost opines that general biological activity is reflected best in nucleus and functional activity is reflected in cytoplasm. [4] .

The basic biological feature of a cell whether be it a proplastic (Cell with an increased activity) or a retroplastic (a degenerating cell) is defined by the chromatin-para chromatin interface. Here the chromatin refers to the condensed, functionally inactive heterochromatin seen in the periphery of a nucleus and parachromatin refers to the distended functionally active chromatin.

The junction is crisp and sharply defined in proplasia as euchromatin is highly active thereby pushing the heterochromatin to the periphery. In retroplasia the junction is blurred and indistinct. Proplasia and retroplasia can be together considered as euplasia or, the normal cell growth. In contrast to a euplastic cell, the morphology of a neoplastic cell is not well defined and exhibits protean features.


   Nuclear Membrane Irregularities Top


The nuclear membrane out line shows a morphology occurring for no reason that can be explained by any normal, retrogressive or progressive processes. Some such features are- pointed spicules, razor sharp angles, and sharp angled infoldings. These features cannot be explained away by blaming an adjacent compressing structure, or an increased activity, or a degenerating nucleus, or due to the technique of rolling and riding during smear preparation, just because of one reason that they rarely happen when it is done to a normal mucosa. In short, the morphology can be described as sharp, grotesque, unpredictable and inexplicable. The so-called chromatin-para chromatin interface is as can be expected in havoc.

Nucleoli in cancer are usually enlarged and numerous in number but if it also shows pointed spicules and sharp angles, then you can almost be sure that you are seeing a sign of danger under the lens.


   Mitoses Top


As is the case for nucleoli so is the case for mitoses. It is not just the abnormal number of these but it is the abnormal morphology that matters, when you are looking for malignant features.


   Nucleo Cytoplasmic Ratio Top


A large and well preserved nucleus at least the size of a macrophage with scanty but well preserved cytoplasm denotes a high N/C ratio, a criteria favoring cancer. A huge draw back of the branch of exfoliative cytology in cancer diagnosis does exist and it lies in the fact that one cannot differentiate a dysplasia, intra epithelial neoplasia, early invasive neoplasia, or advanvced carcinoma because each of these condition show all the above atypical features. In essence, to differentiate from a normal person one can type a patient as abnormal but for a pinpoint accuracy, biopsy is mandatory.

The format for reporting and interpretation of smears into five classes has been discussed elsewhere [5] .

Exfoliative cytology in cases other than cancer is neither sensitive nor specific. Numerous studies on a host of conditions like iron deficiency, Diabetes Mellitus, smoking, alcoholism, pregnancy, ageing, etc, have been done but the diagnostic value and significance are questionable.


   Viral Lesions Top


Few viruses like HPV, Herpes, etc have the capacity to induce excessive nuclear protein production resulting in bizarre giant cells. Oral hairy leukoplakia, which is caused by EBV, shows a pathognomonic nuclear margination and clumping of chromatin [6] .


   Micronuclei Top
[4]

These are chromosonne fragments that remain excluded from the nucleus after mitosis and may serve as markers for increased cancer risk since they have been reported to arise in response to DNA damaging agents. These have also been used as markers for improvement in chemopreventive trials.


   Exfoliative Cytology in Mass Screening Program Top


Even with a history of over 150 years it was only in relatively recent years that the idea of screening for early detection of cancer has gained wide acceptance. The criteria for early detection and screening were out lined and discussed in detail by Cochrane and Holland [4] . Mass screening programs have been successfully worked outt only for cervical cancer. In a set up like India where incidence of tobacco usage is dangerously high, it must he adopted as a part of national health policy.

Obtaining smears from all the 100 crore individuals is nor practical and is unnecessary. Preliminary visual screening for selecting suspicious cases will reduce the workload. In spite of that the workload is magnanimous.

A seasoned cytopathologist is expected to see around So slides in an eight hour working day without getting affected by fatigue and to avoid a subconscious reporting due to monotony. For suspicious cases, and a single patient with multiple affected sites, the time spent on individual slide increases, so the necessity of more trained personnel is needless to be mentioned.

Automation of cytology has been done and two such systems approved by FDA (food and drug association) are i n vogue for cervical cancer the PAP NET system and AUTO PAP300QC. It was also showed that there was a decrease in false negatives with these systems. Assessing more number of slides and more areas per patient was possible in lesser time and without any observer bias (inter or intra) and the factor of fatigue is totally eliminated.

A prospective 'sweeping-effect' on oral cancer over an entire population in shortest time is possible only with such systems but that is not the end. A gradual fading off of human involvement and a gradual adoption of the A1 (artificial intelligence) should Be done. For all positive cases or suspicious cases, the ultimate judge should be the human eye as, a cent percent reliable eyhcr diagnosis is neither feasible nordesirable.


   Advantages Top

".... i consider, for the benefit of my patients and abstain from whatever is deleterious " - Hippocrates' aoth [7]

  1. It is a painless, bloodless noninvasive, quick and simple procedure.
  2. Suitable in patients with systemic disease who are contraindicated for biopsy.
  3. Guards against false negative biopsy.
  4. Post biopsy complications can be eliminated.



   Disadvantages Top


  1. Relatively less information when compared to a histological slide.
  2. Positive results are reliable but negative are not.
  3. Suitable only for epithelial tissues or for tissues exfoliating cells into reasonably accessible sites.
  4. It is only an adjuvant and not a substitute for a biopsy.
  5. Interpretation requires a skilled cyto patholog­ist.
  6. Tumour grading cannot be assessed.


False positivity is a common draw back for exfoliative cytology, but is it imminent'' [13]

Answer is a big no. The defect in a majority of false positive cases lies in the users and not with the science. A false positive case may be due to "early minimal degenerative changes" resulting from processing artifacts like improper fixation or air drying causing "cell bleeding" and an increased N/C ratio, nuclear wrinkling and the like. So, if the technique is good the results are always better.


   Applications Top
[8],[9],[10],[11]

  1. Early detection and control of oral cancer
  2. Microbial diseases and dennatological lesions
  3. Assessment ofnutritionalstatus-Fedeficiency
  4. Forensic dentistry.


Exfoliated cells are a valuable material for personal identification. In a variety of situations like sipping a glass, brushing, biting a fruit, wetting the back of a stamp, dried saliva of a spit, etc. to mention as few, the suspect leaves behind evidence in the form of exfoliated cells.


   Recent Applications Top
[12]

A quick browsing through the search engines reveals that a number of special procedure can be performed on exfoliated cells like IHC, ICC, PCR., flow cytometry, image analysis, neural networking, interphase cytogenetics, southern blotting, special staining for infections, ISH,…. the list is long and never ending and demonstrates the scope of this branch in disease diagnosis.


   Imprint Cytology Top


One of the important factors governing the success of a tumour is the loss of cohesiveness. With the aid of Imprint cytology the same feature can lead the malignancy to its graveyard. The procedure involves a gentle grazing or skidding of a glass slide over the cut surface of a resected tumor immediately after surgery. This followed by PAP staining will detect tumour margin positivity in less than 20 minutes. The surgeon now gets a directive as to which site he should perform an extra clearance there by avoiding majority of recurrences. Every pathologist and surgeon must adopt this technique which is feasible and economical in any surgical setup.


   A Defence to Cytopathology Top


Cytopathology is a practice of medicine and represents a medical consultation demanding a commitment to quality service. To say how good we are in cytopathology, or even if good how consistently are we good, a quality control and standard quality techniques should be followed. These among others include external consultations, cyto-histo correlation, hierarchic review of cytopathological slides, clinical correlation, etc. In a review of profiles of numerous high-end pathology laboratories, a separate department of cytopathology of its own right with a dean or director and a full set of technical and non-technical staff are seen.

Though it is not a necessity in an oral pathology set up, it is at least time to include more of this neglected branch in routine diagnosis. In a country where "lack of success" attributed to lack of infrastructure is being voiced out every other minute, it is ironic that an economic technique such as this is neglected to this extent. In few dental schools, the branch of exfoliative cytology is restricted to those postgraduates worried about finishing a formality called "thesis"

It is true that cytology is no match for biopsy in a final diagnosis but the conversed is true for cytology when mass screening and morbidity cleansing is targeted. Not just considering this as 'Yet another article on exfoliative cytology' or an 'article marketing cytology' steps should be taken to revive this specialty even before the era of 'frame a title grab the reader's eye' technique fails to work on the branch of oral exfoliative cytology.

 
   References Top

1.Oral exfoliative cytology: review of methods of assessment. Ogden GR, Cowpe JG, Wight AJ. J Oral Pathol Med. 1997; 26: 201-5  Back to cited text no. 1    
2.The diagnostic perspectives of oral exfoliative cytology- an over view. Bijoy Kurnar Das, Mallik NC. JIDA 2000; 71: 7-9  Back to cited text no. 2    
3.The clinical value of oral cytology. Gustav J Selbach, Emmerich Von Haam. Acta Cytologica 1963; 7(6) 337  Back to cited text no. 3    
4.Comprehensive cytopathology. Bibbo. IInd edition 1997.  Back to cited text no. 4    
5.A textbook of oral pathology. Shafer, Hine and Levy. 4 th edition. 1983  Back to cited text no. 5    
6.Textbook of oral medicine. Burkett. Ninth edition.  Back to cited text no. 6    
7.Stedman's medical dictionary.  Back to cited text no. 7    
8.Diagnostic cells in scrape cytology in squamous-cell-carcinoma. Acta Cytologica 2001;45(6) 1085  Back to cited text no. 8    
9.Application of ultra fast Papanicolou stain to body fluid cytology. Grace CHYang, Juliana Papellas, Horace C wu, Gerry Waisman. Acta Cytologica2001;45(2) 185  Back to cited text no. 9    
10.Oral exfoliative cytology in the diagnosis of paracoccidioidomycosis. Marcelo Sivieri de Araujo, Ricardo Alves Mcquita, Luciana Correa, Suzana Orsini, Machado de Sousa. Acta Cytologica 2001; 45(3): 360.  Back to cited text no. 10    
11.Benign cellular changes in PAP smear: causes and significance. Shazli N Malik, Edward J Wilkinson, Peter A Drew, Nancy S Hardt. Acta Cytologica 2001; 45(l ): 55  Back to cited text no. 11    
12.Update on special techniques in routine cytopathology. Buley ID. .J Clin Pathology. 1993;40:881.  Back to cited text no. 12    
13.Quantitative exfoliative cytology of normal and abnormal oral mucosal squames: preliminary communication. Jonathan C Cowpe. J Royal society of Medicine. 1984; 77: 928  Back to cited text no. 13    




 

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    Introduction
    Definition
    Historical Evolution
    Rationale of Exf...
    Technique
    Why PAP After All?
    Interpretation
    Nuclear Membrane...
    Mitoses
    Nucleo Cytoplasm...
    Viral Lesions
    Micronuclei
    Exfoliative Cyto...
    Advantages
    Disadvantages
    Applications
    Recent Applications
    Imprint Cytology
    A Defence to Cyt...
    References

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