Indian Journal of Dental Research

ORIGINAL RESEARCH
Year
: 2011  |  Volume : 22  |  Issue : 1  |  Page : 62--65

Role of deeper sections in diagnostic oral histopathology: A retrospective study


Ravikanth Manyam, K Reena, TR Saraswathi 
 Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India

Correspondence Address:
Ravikanth Manyam
Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram, Andhra Pradesh
India

Abstract

Background: Histopathology is a gold standard diagnostic tool for many lesions. Interpretation of tissue sections is a pivotal step in giving the diagnosis. Usually, initial tissue sections may not show complete features of the lesion, so deeper sections of the specimen may play a significant role at times for final diagnosis. In small biopsy specimens, deeper sectioning is routinely used in many laboratories to enhance the sensitivity and accuracy of the diagnosis. Aim: To analyze the percentage of deeper sections taken and its significance in the final diagnosis of oral lesions. Materials and Methods: A total of 500 cases from the files of Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram, Andhra Pradesh were analyzed, and cases of deeper sections were selected. The present retrospective study involves comparison of initial histological findings with those seen in deeper tissue levels of same specimen. Results: 40 cases (8%) were selected for our analysis. Out of these, 19 cases (47.5%) required deeper sections as the initial sections were superficial and undiagnostic. 21 (52.5%) cases were advised for additional sections to confirm, rule out or clarify certain diagnoses, out of which 15 (37.5%) disclosed additional pathological findings, whereas 6 cases (15%) showed the same histological features. Conclusions: Diagnostic laboratories must balance the utility of deeper levels with the additional time required and expense incurred and the impact on patient care. Deeper sections are inevitable in certain situations and periodical auditing of laboratory work will reduce the need for additional sections and delay in the dispatch of biopsy report.



How to cite this article:
Manyam R, Reena K, Saraswathi T R. Role of deeper sections in diagnostic oral histopathology: A retrospective study.Indian J Dent Res 2011;22:62-65


How to cite this URL:
Manyam R, Reena K, Saraswathi T R. Role of deeper sections in diagnostic oral histopathology: A retrospective study. Indian J Dent Res [serial online] 2011 [cited 2014 Sep 17 ];22:62-65
Available from: http://www.ijdr.in/text.asp?2011/22/1/62/79980


Full Text

Biopsy is the removal of tissue from the living organism for the purpose of microscopic examination and diagnosis. Histopathological diagnosis helps in clinical management of the patient for better prognosis. It is considered that the diagnosis of many lesions can be made clinically by the dentist but it is only a provisional one. The final diagnosis depends upon the report given by the pathologist. [1] The pathologist may require sections at different levels to be examined for final diagnosis and such situations necessitate the need for deeper sectioning.

Different types of sections can be obtained from the tissue block based on the requirements. Serial sectioning is defined as obtaining a continuous ribbon of sections from a paraffin block and placing all the sections on multiple slides. [2] Serial sections are meant for the analysis of tissue changes at different measured depths of the sections taken. In step sectioning, sections are discarded in between the sections that are mounted on the glass slide. [3] Step sections are preferred to serial sections as the intervening unstained sections are available for special stains if needed [4] or can be retained for future usage. Traditionally, deeper levels are obtained, at the request of the pathologist, after the original slides have been reviewed - retrospective step sections. In some laboratories, step sections are prepared prior to receipt of the slides by the histopathologist - prospective step sections. [5] Deeper sections are needed to identify positive areas that could contribute to a proper diagnosis and are used sometimes interchangeably with serial and step sections.

Deeper levels of small biopsy specimens, especially needle core and endoscopic biopsies, are commonly used to enhance diagnostic sensitivity and accuracy. [2],[6],[7],[8] Studies suggest that deeper levels provide a more accurate diagnosis in about one-third of skin biopsy specimens and they are most helpful in the diagnosis of skin cancer. [9],[10],[11] The utility of deeper levels in oral histopathology has not been rigorously assessed. The aim of this study is to analyze the percentage of deeper sections requested and their role in the final diagnosis, from the slides available in the Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram, Andhra Pradesh.

 Materials and Methods



A total of 500 cases from the files of Department of Oral and Maxillofacial Pathology collected from 21 January 2004 to 11 February 2008 were studied retrospectively. We did not restrict this study to any individual lesion but included all the lesions that were reported in the department for which deeper sections were taken. Slides with deeper levels for the purpose of better staining or special staining were excluded. Slides carrying the label as "deeper sections" as well as the corresponding "initial sections" were reviewed. The provisional diagnosis and histopathological diagnosis were noted. The reasons for which the deeper levels were taken were classified as initial sections were superficial and undiagnostic, and to look for additional histological findings, though diagnosis was possible from the initial slide. The results were analyzed. This study design did not explicitly observe the question of how many deeper levels are required for the diagnosis. This study was carried out by group of three oral pathologists (authors) together in a visual monitor screen, so inter-observer variability is avoided.

 Results



Forty (8%) cases were advised for deeper sections out of 500 cases. In 19 cases (47.5%), deeper sections were required as the initial sections were superficial and undiagnostic, representing only a part of the biopsy tissue. Deeper levels in 21 (52.5%) cases were taken to look for additional histological features, even though diagnosis was possible from the initial slide. This was to improve diagnostic sensitivity or to confirm the initial diagnosis rendered using the initial slide. Out of these 21 cases, 15 (37.5%) disclosed additional pathological findings, whereas 6 cases (15%) showed the same histological features in deeper sections.

 Discussion



The histopathology report is an anxiously awaited document from the Department of Pathology by the surgeon. Delay in diagnosis will definitely have an impact on patient care. Some of the many reasons for the delay in reaching the final diagnosis are poorly fixed or damaged specimen during removal, unrepresentative of the lesion or too small tissue, plane of the section not including the critical feature [12] and superficial sections. [13],[14] Though deeper sections are contributory for the histopathological diagnosis, the procedure of sectioning and staining definitely involves time and cause delay in dispatching the report. In this study, 8% of the cases needed deeper sections. Of this, in 47.5% of cases, the initial sections were superficial [Figure 1] and [Figure 2].{Figure 1}{Figure 2}

Proper supervision and training of the laboratory technician in terms of orientation of the tissue will minimize the chances of deeper sections. This can be done by either inking the biopsy specimen [15] or by recording the three-dimensional appearance of biopsy tissue with size and shape. Both these procedures will guide the technician in avoiding superficial sections, as he cuts the block till it corresponds to the diagrammatic representation of the specimen that was drawn or to observe the complete peripheral black inking of the specimen. Studies suggest that it is advisable to obtain deeper levels when the biopsy sections are oriented incorrectly or the histological findings are unclear in initial sections. [2],[16]

Deeper sections are also requested seeking additional histological features in spite of the initial slide being diagnostic. In this study, such a requisition was made in 21 (52.5%) cases. Within them, in 15 cases (37.5%) deeper sections disclosed additional pathological findings and 6 cases (15%) showed the same histological features. For example, in a case of pyogenic granuloma of the gingiva, the deeper section showed areas of calcification resembling cementum [Figure 3] and [Figure 4]. In another case, the initial section showed early invasive squamous cell carcinoma. Anticipating that there may be additional areas of deep invasion, deeper section was advised. But the areas of invasion appeared the same as in the initial slide [Figure 5] and [Figure 6]. Examination of multiple levels has been cited as a means of avoiding diagnostic error and subsequent malpractice claims. [17] In gastrointestinal pathology, the diagnostic efficacy of additional step sections in colorectal biopsies originally diagnosed as normal, yielded new diagnostic information such as tubular adenoma and lymphocystic colitis in deeper sections. [18] {Figure 3}{Figure 4}{Figure 5}{Figure 6}

Bruecks et al.[5] reported that the step sections (three slides at 50 μm intervals) resulted in new findings in 7% of small skin biopsies or curettings. In a study by Carag et al., [10] step sections (10 slides at 50 μm intervals) revealed new diagnostic findings in 33% of biopsies with an initial diagnosis of actinic keratosis.

Cystic lesions like dentigerous/odontogenic keratocyst or neoplasms like cystic ameloblastoma will have thin tissue that will be curled during the processing. Even with careful orientation, the sections may not show the complete epithelial lining [Figure 7] and [Figure 8]. There is no guidance for the technician to assess the depth of the tissue, even if the diagrammatic representation or inking the specimen was available, and therefore, deeper sections are mandatory.{Figure 7}{Figure 8}

Even though obtaining deeper levels will undoubtedly provide an accurate diagnosis, the additional time required for the process and expenses incurred should not be overlooked. Additional time will be needed to retrieve the block, label slides, and section the block, mounting and evaluation of the slide by the pathologist. Apart from labor costs, generation of additional slides does incur added supply costs. These include costs for chemicals, equipment use, glass slides, cover slips and the need for increased slide storage space. Bruecks et al.[5] examined the utility of prospective step sections in improving diagnostic accuracy and turn-around time for small skin biopsies. They used a time-motion, task analysis approach to assess the technical labor costs of prospective step sections versus retrospective step sections. They concluded that the use of prospective step sections is essentially cost neutral and case turn-around time is improved by 9-45%.

 Conclusion



It is advisable to take deeper sections when the initial section is not revealing the complete histological features. If there is any uncertainty in the histological diagnosis, it is always advisable to examine deeper sections of the tissue for remitting better therapeutic needs for the patients. Proper supervision and training of the laboratory technician in terms of orientation of the tissue will minimize the chances of additional sections. Deeper levels are inevitable in certain situations and periodical auditing of laboratory work will reduce their need and a delay in the dispatch of biopsy report is avoided by taking prospective step sections in clinically suspicious lesions. The utility of deeper sections in specific oral lesions should be evaluated.

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