4 DISCUSSION
According to our findings, malignancy is associated with a single abnormal vascular pattern on the surface of the vocal cords, whereas leukoplakia might be associated with either normal or many abnormal vascular patterns. In addition, we discovered that in patients with leukoplakia, the length of time spent smoking (in years) had a detrimental impact on the surface and vascularization of the voice cords. The number of cigarettes smoked each day did not seem to make a difference.
Capillaries in the surface lamina propria, smaller arteries and veins, as well as arterioles and venules in the deeper layers, characterize the vascular microanatomy of human vocal folds. Arterioles and venules have direct vascular anastomoses.15
Under rigid laryngeal endoscopy, vocal cord leukoplakia presents as a white or grayish confined patch, distributed granule, or verrucous structure. It may have one or more localizations.10Leukoplakia is a chameleon-like epithelial transformation that can range from benign thickening to malignant tumors. As a result, the name ”leukoplakia” is insufficient to characterize the lesion’s histological identity.10-13
There are previous reports on a tissue-specific classification of vascular changes associated with laryngeal leukoplakia. They finally have found that age, non-homogenous lesion texture and existence of hyperemia are independent predictors of malignancy.14-16 Their results support the findings of the present study to some extent because they also have found that age and lesion texture may predict prognosis. However, these authors have not further explored the impact of age on leukoplakia lesions. Our study provides evidence that age may be related to the development of this disease. Moreover, a further novelty of the present study is that a very detailed study on the lesion texture has been conducted. Leukoplakia lesions have traditionally been divided into two categories from their appearances which were individually homogenous and heterogeneous in many reports.17
Although new endoscopic tools, such as narrow band imaging, optical coherence tomography and contact endoscopy have been developed to improve the diagnosis of vocal fold leukoplakia, WL laryngoscopy is most applied in clinical practice.18-21 The ability of rigid or flexible laryngoscopy to visualize and characterize lesions of vocal cords continues to improve.
Many researchers have reported high efficacy of CE in diagnosis of mucosal lesions not only of larynx, but in other sites of head and neck as well.10,12,23-25 These results have been obtained taking the histopathological examination as the gold standard. However, the technique of CE has definite advantages and limitations. Contact endoscopy enables visualization of tumor margins, dysplasia, and normal epithelium, thus offering the possibility of more precise complete removal of laryngeal lesions in a single sitting. Along with in vivo studies, contact endoscopy can also be used to analyze the excised segment of the lesion and hence ensure whether the lesion has been completely resected. The grade of dysplasia is indicated by the impaired nucleus/cytoplasm ratio, nuclear hyperchromasia, and variation in the number and appearance of the nucleoli. 21,23
Of course, there are limitations in the use of CE, which should be also considered in the interpretation and validation of the results of the present study. Two inherent limitations are the inability to detect very early dysplasia and the inability of differentiation of carcinoma in situ from invasive carcinoma.