Correlation Between Clinical and Histopathologic Diagnosis of Oral Potentially Malignant Disorder and Oral Squamous Cell Carcinoma

Objective: To determine the frequency of oral potentially malignant disorders and Oral Squamous Cell Carcinoma (OSCC) and evaluate the consistency between their clinical and pathological features. Material and Methods: This retrospective study was conducted on records with a diagnosis of oral leukoplakia, oral erythroplakia, erythroleukoplakia, actinic cheilitis, lichen planus, and OSCC in the Pathology Department of Kerman dental school from September 1997 to September 2017. Data were analyzed in SPSS 21 at the significance level of ≤5%. Results: There were 378 cases of oral potentially malignant disorders and 70 cases of OSCC with a mean age of 46.82 ± 15.24 years. Buccal mucosa was the most frequent site, and lichen planus the most common lesion. Females were significantly older than males in leukoplakia and carcinoma in situ lesions. Clinical diagnosis and histopathology were consistent in 69.03% of cases. Conclusion: Clinical and histopathological diagnoses were consistent in 69.03% of records. The highest degree of clinical compliance with histopathology was observed in OSCC. Dentists should pay attention to oral potentially malignant disorders for early diagnosis to prevent their transformation to malignancy.


Introduction
Oral cancer is the sixth most common cancer with varying prevalence around the world [1]. Oral squamous cell carcinoma (OSCC) is the most common cancer of the oral cavity and accounts for 95% of all oral cavity cancer instances [2]. OSCC is diagnosed based on clinical examinations and histological findings of oral biopsy [1]. The 5-year survival rate of OSCC has remained around 50% over the last three decades [3].
Early diagnosis and treatment of malignancy usually improve long-term treatment and survival rate [4]. Previous conditions conducive to cancer are referred to as premalignant lesions. These lesions are morphologically altered tissues observed in clinical examinations that are more likely than normal tissues to develop into cancer [5,6]. These lesions may be precancerous or premalignant and show epithelial dysplasia in histopathologic examinations [6].
The World Health Organization prefers the term "Oral Potentially Malignant Disorders" (OPMD) for lesions that are clinically prone to develop into oral cancer [7,8], such as leukoplakia, erythroplakia, lichen planus, hyperkeratosis [5], and submucous fibrosis [9]. This term has been introduced because studies have shown that all precancerous lesions do not progress to malignancy, and some are reversible by discontinuation of a habit [5].
Maia et al. [11] found that 31.2% had OPMD. Regarding the relationship between clinical and histopathologic diagnoses, the highest consistency was observed in erythroplakia and atypical ulcers. A variety of diagnoses from hyperkeratosis to severe dysplasia was seen between six pathologists. Fitty point five (50.5) percent of pathologists accurately diagnosed mild-to-moderate dysplasia [12].
In addition to clinical features, microscopic and radiographic views of the lesions are necessary for a definitive diagnosis [13]. Early diagnosis of OPMD has a great clinical significance in preventing disease development and achieving more successful treatments. As a result, it increases the life expectancy and quality of life for patients. Therefore, in continuing our interest in the medical research [14][15][16] and given the varied prevalence and type of premalignant and malignant lesions in different societies and the fact that clinical features cannot provide definitive diagnoses for several lesions, the consistency of clinical and histopathologic diagnoses gains significance for definitive, precise, and, particularly, early diagnoses of premalignant lesions as the main goal of treatment. Accordingly, the present study aimed to evaluate the consistency between the clinical and histopathological features of oral potentially malignant disorders and oral squamous cell carcinoma in a 20year period.

Study Design
This was a retrospective descriptive-analytical whose population included the medical records of the maxillofacial Pathology Department of Kerman University of Medical Sciences School of Dentistry from September 1997 to September 2017.

Data Collection
In this regard, a trained senior student and an expert oral pathologist reviewed the department archive. All premalignant lesions (lichen planus, leukoplakia, erythroplakia, hyperkeratosis, actinic cheilitis) and OSCC were identified and microscopic diagnosis was confirmed. Records with descriptive histopathologic diagnoses, i.e., without definitive microscopic diagnosis despite clinical diagnosis of leukoplakia and erythroplakia, were reevaluated and excluded if definitive histopathologic diagnoses were not possible.

Results
A total of 404 cases of oral potentially malignant lesions and SCC were evaluated. The mean patient age was 46.82 ±15.22 years; 57.6% of lesions were in men and 42.4% in women. Buccal mucosa was the most common lesion site with 294 cases (72.05%), followed by tongue with 75 cases (18.38%) (Figure 1).

Figure 1. Lesions distribution according to the area.
According to histopathologic diagnoses, out of 408 cases, lichen planus was observed in 282 cases (69.8%), followed by SCC in 67 cases (17.32%). Figure 2 presents the distribution frequency of lesions based on the histopathologic diagnosis.
The mean age of women was significantly higher than males (p=0.61). Moreover, the mean age of OSCC patients (59.44 ± 17.55 years) was higher than those with OPMD. The lowest mean age (45.14 ± 13.71) was observed in lichen planus patients. Correlation between the mean age of gender with different lesions is shown in Table 1. There was no significant difference between men and women's mean age in lichen planus,

Discussion
The possibility of OPMD developing into carcinoma has been reported in 5-18% of cases [17,18]. In the present study, the mean patient age was 46.82 ± 15.22 years. Similar studies showed the mean age of OPMD patients was 56.09 [11] and 55 years [19], slightly higher than the current study.
This research revealed that 57.6% of lesions were in men and 42.4% in women. In a study by Casparis et al. [20], 38.2% of lesions were observed in men and 61.6% in women. This finding is not consistent with the current research results, which may be accounted for by varying types of lesion in these studies.
Buccal mucosa was the most common lesion site in the present research. Lower lip and oral mucosa [10] and oral mucosa and alveolar ridge [11] lower lip and palate [21] was the most frequent location. In the present study, lichen planus was the most frequent lesion occurring most commonly in buccal mucosa; therefore, this can justify buccal mucosa as the most common lesion site in this research.
Lichen planus, found in 69.8% of the cases, was the most frequent potentially malignant lesion in the present study. This finding was inconsistent with the other studies [11] actinic cheilitis as the most frequent lesion and leukoplakia as the most common lesion [22][23][24][25]. In a systematic review, 85 out of 7806 cases of oral lichen planus and 4 out of 125 cases of lichenoid lesions progressed to SCC. The malignancy progress rate was 0%-3.5% in different studies [25]. In this study, lichen planus was more common in women than in men. The mean patient age was 45.14 ± 13.71 years. This finding is consistent with other studies [19,26,27].

Chielitis Glandularis
Buccal mucosa was the most common site for lichen planus. According to literature, oral mucosa is the most common site for oral lichen planus. The epithelium's thickness and the degree of oral keratinization are believed to be the reasons [28].
In the current study, 17.32% of lesions were SCC with a mean patient age of 59.44 ± 17.55 years and a higher prevalence in women than in men. The mean age of women was higher, albeit with no significant difference. This finding differs from similar studies in which the lesion was more common in men [19,28]. This difference can be attributed to the higher frequency of women visiting dental centers.
In this study, leukoplakia accounted for 7.92% of lesions. Leukoplakia has been reported as the most common OPMD in many studies [22,29,30]. The global prevalence of leukoplakia is 2.6% [31]. This difference can be attributed to the study population and method. Leukoplakia was more common in men than in women in the present study. This finding is consistent with the study of Vázquez-Álvarez et al. [32]. The mean age of patients with leukoplakia was 49.54 ± 12.93. Women were significantly older than men. Most cases of oral leukoplakia were shown to occur in the third to fifth decades of life in developing countries, whereas the majority were over 40 years of age in developed countries [33]. Leukoplakia is called OPMD.
This term does not indicate the severity of the disease and the potential for developing into a malignancy [5].
The progression risk to malignancy was reported between 0.13 and 34% [34].
Seven cases of dysplasia were observed in the current study. It was shown that dysplasia of the oral cavity might show the lichenoid histology, which can cover its potentially malignant appearance [35].
In this study, carcinoma in situ accounted for 2.06% of the lesions. According to some specialists, carcinoma in situ is a precancerous lesion, while others believe that the lesion is a real malignancy discovered before invasion [34].
The clinical diagnosis was consistent with histopathologic diagnosis in 69.03% of the cases. In Abidullah et al. study [36], clinicopathologic relationship of 100 white lesions was 78% and Maia et al. [11] showed that the potentially malignant oral lesions were 78.1%. This difference may arise from the type of study.
The highest percentage of correlation between clinical and histopathological diagnosis was observed in OSCC. This may be because the samples were from the School of Dentistry and oral specialists are completely familiar with the clinical manifestations of OSCC.
Oral leukoplakia reached 40% of coincidence between clinical and histopathological diagnoses. This may be that since leukoplakia is a clinical term and does not indicate a specific histopathological presentation, the degree of clinical presentation with histopathology has been low. In the current study, clinical and histopathological diagnoses were inconsistent in all erythroplakia cases. It has been shown that 90% of the erythroplakia lesions are histopathologically severe dysplasia, carcinoma in situ, or superficial invasive squamous cell carcinoma [37].
It was shown that increased experience of a surgeon and greater association with pathologists could reduce the difference between clinical diagnosis and histopathology [38]. The difference in the clinical and histopathologic diagnoses might be partly caused by the fact that the clinical information did not accompany the biopsy specimen and the pathologist was not aware of the clinical presentation and exact location of the lesion. In addition to clinical features, the microscopic examination and radiographic view of the lesions are necessary for a definitive diagnosis [13].

Conclusion
Lichen planus was the most common lesion and buccal mucosa was the most common site. The lesions were more prevalent in males. In 69.03% of cases, clinical diagnosis was consistent with the histopathologic diagnosis. The highest percentage of correlation between clinical and histopathological diagnosis was observed in oral squamous cell carcinoma. Further studies are recommended on the risk factors associated with oral potentially malignant disorders.